Adapted from THE INTIMATE ANIMAL by Justin Garcia, PhD. Copyright © 2026 by Justin R. Garcia. Used with permission of Little, Brown Spark, an imprint of Little, Brown and Company. New York, NY. All rights reserved. CARE Jen and Dave’s second child was born in November 2002. Two weeks la ter, on a cold Thursday night, the phone rang. It was Dave calling to say Jen needed to go to the hospital. Now. Could my mom come over to watch their two kids? This was alarming but not entirely unexpected; Jen hadn’t been herself. Since giving birth to Alexis (Lexi, we would call her), Jen had been forgetting things. More than once, she’d dropped a glass or something one of us handed to her — almost as if her eyesight was off. She was also having headaches so debilitating that she had been telling people not to come by and see the baby. Although it seemed things had been smoother after the birth of their first daughter, Emily, about three years earlier, we had all been thinking maybe this was a normal postpartum reaction: a mix of hormones furiously adjusting, lack of sleep, and the distraction of caring for a newborn. This was what the physicians and nurses had suggested in response to Dave’s concerns the week before. But suddenly Jen’s condition didn’t seem normal anymore. My mom and stepfather agreed to take the kids, and as a teenager, my job was to play with Emily and distract her from her mom’s absence. What unfolded over the next couple of days happened really, really fast. Jen’s headaches and dizziness were attributed to a cyst on her brain, which turned into an emergency surgery in which her skull was opened, which turned into days spent looking pale and small in her hospital bed, her head swathed in white gauze. For the rest of the family, those agonizing days were spent switching between helping care for their little girls and tagging out with Dave to sit by Jen’s side as she recovered. I couldn’t help but watch Dave’s face as he watched his wife’s. They’d always been so in love, so in sync with each other, and that bond between them was palpable even in this horrible moment filled with fear and uncertainty, with sadness and anger that no one knew where to direct. Her eyelids fluttered. His normally steady jaw drooped, as if to draw any pain from Jen’s body into his own. His thumb swept the back of her hand lightly, sweetly. When a hank of blond hair slipped over her freckled cheek, Dave tucked it back behind her ear as tenderly as if he were stroking one of their daughters’ faces. I remember thinking that the look on Dave’s face as he regarded his gravely ill wife was an expression of the intense love that human beings live and die for, and that we should all be so lucky to have someone who looks at us the way Dave looked at Jen. They were together in sickness and in health, until death — years later — ultimately forced them apart. Life‑threatening or unexpected health issues have the potential to redefine a relationship. For some, that can mean starting a new chapter of deeper connection, but for countless others it’s the end of everything. KARMIC INSTABILITY The first wedding I ever officiated was for two friends from graduate school whom I had introduced at a local bar following a costume-themed house party. Sam and Alex had instant chemistry on the dance floor that night and started dating that week. Fewer than three months into this new relationship, disaster struck in the form of Tropical Storm Lee, which crashed through the town we lived in and flooded Alex’s apartment building; Sam invited Alex to move in while the cleanup crews did their work, but temporary turned permanent, and a few years later, from their new shared nest in a new town, they asked me to perform the wedding ceremony. I was delighted and honored. Sitting down to write the words for their wedding ceremony was the first time I had thought critically about that common nuptial phrase “in sickness and in health.” I began to wonder whether the phrase really has any teeth to it, and whether the concept had been well studied. How much do we really know about whether people actually do stay through the “in sickness” part? Jen was sick on and off for years. What the doctors had initially thought was a cyst turned out to be brain cancer, an astrocytoma. There would be days, even months, when it seemed the cancer was behind her, and then days and weeks when it was an effort for her to even leave the house. Then there were the horrendous brain surgeries every few years, like clockwork. From the moment she was diagnosed, the family unit had reoriented itself to revolve almost entirely around her illness. In addition to the stress of never knowing when — or if — she would get better, Jen and Dave faced enormous expenses, including traveling internationally to try nontraditional treatments, amassing a mountain of medical bills despite their good insurance. As a family, we rallied around them, offering emotional support and pitching in financially when things got tight. Friends and family spoke of their admiration for Jen’s fortitude, but I couldn’t help noticing that people also murmured their admiration for Dave’s fortitude. I would later learn, and understand why, some clinicians and researchers call some cancers a “we‑disease.” Jen and Dave faced all the predictable challenges and struggles that come with marriage and raising children, along with the extra burdens of navigating an unpredictable illness. The pressures were enormous, but Dave always showed up, never wavering in his love or readiness to care for his wife and their daughters. At one point, they shared with me that the two of them had talked openly about whether their relationship could weather the storm of the cancer. Each time they got to the point where they began to doubt the strength of their pair bond, they actively chose to stay together; the intimacy they had forged as young lovers had become a sustaining force. Research has shown that not all intimate relationships are able to weather the same kinds of storms. Studies of couples who have lost a child suggest that extreme trauma and grief tend to either split the parents up or bring them closer together. In one such study, many couples reported a subsequent decline in sexual activity, with some noting it was a painful reminder of how the child they lost had initially been conceived. And in one German study of partners and ex‑partners of cancer patients, among those who had split up more than half (nearly six out of ten) reported that cancer had contributed to the separation. Not all relationships handle difficulties the same way. Image: Deposit Photos. If you’re watching the person you love struggle to survive an illness, things aren’t going to be the same — for better or for worse. When weathering the storms of illness, grief, and loss, the goal should not be to get back to how things were. Instead, “success” is about managing adversity and embracing a “new normal.” Social psychologists have described a uniquely human phenomenon known as the “just‑world fallacy,” which is a fundamental belief we have that the universe is fair, and therefore bad things happen for a reason. This is at least part of the reason we have a hard time understanding when someone we perceive as innocent is wronged — and when we encounter circumstances that we have a hard time understanding, the human mind tries to come up with a rationale, which can sometimes lead us to unrealistic conclusions. A man is mugged in the park while jogging; someone asks, “How late at night was he out?” It’s fundamentally the wrong question, but our unconscious bias leads us to insist he must have done something to precipitate this horrible and statistically rare event so that we don’t have to wrap our minds around the fact that there are people out there who cause violence without provocation. This bias carries over into relationships. A couple that loses a child, for example, seeks meaning in the meaningless as a way to explain and justify their trauma — and pretty soon they can start to find sources of blame in each other. Sometimes a parent is guilty of actions born of not knowing better or not caring, but more often this type of questioning merely creates a vicious cycle of resentment and blame. Our intimate relationships provide safety, stability, and reassurance, even and perhaps especially when we are in pain. They are both a container and a salve for our psychic wounds. But in our worst states of vulnerability and anguish, our partners can become a target of our pain; in some studies, couples who experienced the sudden death of a child directed their psychological distress and hostility toward each other, perhaps unintentionally. When we are intimate with someone, we feel safe enough to lash out, with the often unspoken understanding that the ties that bind us to our partner are strong enough to survive our emotional attacks. But when those ties aren’t strong enough, when we begin to damage the very structure that provides us refuge, the pain we feel is compounded. Whether the couple stays together or not, a loss of such magnitude is just too intense a trauma for the relationship to stay the same as it once was. THE HEALING HIGHWAY OF CARE My Kinsey Institute colleague Sue Carter and I walked across campus one afternoon, noticing the first signs of spring. Daffodils bloomed through the mulch, birds sang from the branches of newly green trees, and college students traipsed around dressed as if the temperature was much warmer than it actually was. Pausing in front of a row of budding magnolias, Sue noted that one of the big‑picture findings of her fifty‑year research career could be boiled down to a simple phrase: “Love truly is the best medicine.” She was referring to the undeniable evidence that healthy and positive close relationships can result in elevated oxytocin and physiological states that actively improve our health; that love and the physiological processes that make such intense feelings and joys of connection possible reduce inflammation, improve immune function, regulate the autonomic nervous system, and may even improve the health of our gut microbiome. Another series of studies reveals that these interactions between relationships and physical health are bidirectional, meaning that just as relationship dynamics can affect our health, our health can also affect our relationship dynamics. In a pack of studies on how individuals and couples experience and cope with illness led by my collaborator Amanda Gesselman, our own lab has found that people with epilepsy, breast cancer survivors and their spouses, those with trauma from adverse childhood experiences, and young men living with HIV all exhibit a similar pattern in their relationships: Their health affects their relationships in measurable ways, and in turn, those relationships affect their health. Sexual function or loss of intimate contact can be a major player. When illness lessens sex drive or makes sex less possible or pleasurable, the partnership suffers. When illnesses impact sexual and reproductive organs, medical decisions around treatment can place an especially heavy burden on couples’ intimate lives. In our work with breast cancer survivors, we observed a consistent finding that many women who undergo cancer-removing mastectomy (the partial or complete surgical removal of one or both breasts) struggle to feel comfortable in their new bodies, and often feel embarrassed by surgical scars. This inevitably impacts the way they behave when trying to be physically and emotionally intimate with their partners, and in some cases includes a lack of desire to be intimate at all. Survivors report grappling with any number of complicated emotions, from shame, anger, and sadness to a sense of mourning that a part of themselves that has defined their femininity has been altered or lost (this is one reason many women’s health advocates have argued for breast reconstruction surgeries to be covered by healthcare insurance, as studies have shown this can dramatically help survivors with their psychosocial health).  The partners of women who have had mastectomies, too, face emotional obstacles when engaging in sexual intimacy — the uncertainty of whether they should acknowledge or ignore their partner’s scars; picking up on their partner’s discomfort but not knowing what to do or how to act; the pain of having to confront visual reminders of their loved one’s trauma. One man I spoke with told me about how once, while they were having sex, he had traced a finger along the twin scars of his wife’s mastectomy, feeling a sense of awe at her bravery and resilience. “No,” she had said simply, grabbing his hand, and he understood. While he saw his wife’s scars as a source of her strength, for her they triggered painful memories of grueling treatments and the fear of leaving her husband a widower, raising their young children alone. The many medications that go hand in hand with illness can affect aspects of our sex lives as well. Some hormonal drugs, for example, can affect libido; some cardiovascular medications can reduce sexual function (penile erection and vaginal lubrication); other drugs might even cause romantic desires and feelings to be altered. Some psychiatric drugs can have similar effects. In one of our unpublished studies, a startling 11 percent of adults using antidepressant medications reported experiencing blunted romantic feelings as a side effect, consistent with a neuropsychiatric theory on the impacts of regulating serotonin proposed by Helen Fisher and J. Andy Thompson. When illnesses impact sexual and reproductive organs, medical decisions around treatment can place an especially heavy burden on couples’ intimate lives. Image: Deposit Photos. One study from Hong Kong of female breast cancer patients and their husbands found that marital adjustment to the realities of breast cancer was strongly associated with the patient’s outlook on the world, their relationship, their treatment, and even their marriage. In other words, our relationships and our health go hand in hand. These are the complex emotional dances couples navigate, in the best cases trying to support each other as needs change in the wake of health concerns, illness, and survivorship. When one partner suffers a trauma, sometimes we hear things like “Well, s/he’s the one who’s actually going through it.” However, while it’s true that others often can’t fully relate to the personal battle of fighting illness, when it comes to a healthy relationship this statement isn’t entirely true. Even if we aren’t the person with the main burden of a disease or illness, we are affected. The literature on caretaking provides mountains of evidence of the toll managing a family member’s illness — termed “caregiver burden” — can take on partners, parents, kids, and the self. Illness damages our bodies, but it can also damage our intimate relationships, precisely at the moment we need them the most. Jen battled her brain cancer for thirteen years. There were days she seemed to be in the clear and days she seemed almost gone; sometimes we held our breath and sometimes we let it out. Five craniotomies. Countless treatments, several experimental. After she had bounced back so many times, we perhaps forgot that she was mortal after all. When it became clear that her illness had gained too much ground in the ongoing war, I was deep into my own career some 800 miles away. But even from this distance, I noticed that over the course of Jen’s illness, Dave had adapted in ways that were hard to fathom. His whole life — career, socialization, ambitions — had shifted to accommodate his wife, her needs, and the needs of their family, which by that point included two beautiful and remarkably resilient little girls, two dogs, and a turtle named Tommy (which we only much later learned was a female). While Jen was the one fighting cancer, both she and Dave had been out on the battlefield, and they would rise and fall together, time and time again. Jen had always been my hero. But the sicker she got, the more I realized that Dave was my hero, too. Their story is a remarkable example of the resilient power of intimate love between two human beings. IN SICKNESS AND IN HEALTH Part of our legacy as the intimate animal is our capacity to bond with others — not just with a romantic partner but also with family members, colleagues, and friends. And in times of illness or trauma, these social relationships can become an essential source of support and care. Work by psychologist Julianne Holt‑Lunstad and others has demonstrated that the absence of quality relationships is a strong predictor of disease and mortality. In one large meta‑analysis comparing data across dozens of studies with a total of over 300,000 people, researchers found a 50 percent increase in survival likelihood as a result of stronger social relationships. When scientists control for the quality of a relationship, even an unsatisfying one might be more beneficial than no relationship at all when it comes to health outcomes. It’s not unlike how having a helicopter parent anxiously hovering around a child’s every move is not ideal for his or her development, yet it’s still better than having no parent or a disengaged one — even if the overly involved kind adds a different kind of stress.  The body responds and adapts to social support in whatever form it comes. There is an interesting nuance to the research on spousal support and social support more generally. While having a supportive partner and close relationships is important, especially in times of urgency or crisis, it’s the perception of support that matters most. That is, it’s not whether you are always available, but whether I believe you’ll be there when I need you most. From the moment she was diagnosed, our whole family became a sort of galaxy orbiting around the black hole of Jen’s health. Her long battle for survival gave us something to rally around, something to unite us in the face of the unimaginable. When she died, we all remained extremely close, but without a center our universe faltered. In the wake of that loss, we did the only thing we could. We turned to Lexi and Emily, the daughters Jen had loved so fiercely but would never get to see graduate from high school and then college, or watch as they got married. We are still a very close family, in many ways still orbiting around Jen’s ghost. Some evolutionists have argued that caring is the trait that ultimately facilitated humans having such remarkable success as a species in terms of survival, reproduction, and global distribution. In particular, sharing — first of food and childcare, later of feelings and intentions — allowed everyone to pitch in and provide for the group. With everyone working together, there was additional high‑nutrient food, allowing humans to evolve larger brains that facilitated more complex social interaction, and eventually more complex social structures. Sharing, as an outgrowth of caring, allowed us to be a super organism, a collective that helped its members and made sure everyone was cared for. In other words, care is not only at the center of our romantic relationships but may have been the key to our species’s evolutionary success. Caring for others has a major influence on our health, well-being, and ability to thrive. Image: Deposit Photos. Over the last decade, scientists have paid increasing attention to the remarkable power of caring, including its evolutionary foundations and significance to our health, well‑being, and ability to thrive. While many people are familiar with the fight‑or‑flight response, the mobilizing of a physiological and behavioral impulse in the face of danger, it turns out this may be a more commonly male response to threat. Females may be more likely to respond with what biopsychologist Shelly Taylor calls tend‑and‑befriend: the attempt to protect offspring (tend) or seek out a social group for mutual defense (befriend). It’s easy to assume that traits such as caring, cooperation, empathy, and fairness are uniquely human. But decades of work by primatologist Frans de Waal shows us that other primates and mammals sometimes exhibit similar patterns, and that these social tendencies are critical to their survival. Other research reveals that humans are not the only animals with the capacity for grief or extreme empathy for others in distress. In 2016, a family of elephants in Samburu National Reserve in northern Kenya was filmed continuing to visit the body of their matriarch for weeks after her death, circling her skeletal remains, probing them gently with their trunks as if they were still trying to process their enormous loss. Magpies have been observed burying the dead under twigs and grass, and chimpanzees have been known to caress those who are nearing death, mourning and grooming them after they are gone, and avoiding the place where they died out of apparent grief. Yet the relentless devotion to another’s well‑being while they are still alive is not something we see in the animal kingdom often. In most species, if a member of a pair bond gets sick, their partner will not stay by their side or display the caring behaviors we observe in human beings. Though many primates will groom each other to remove disease‑carrying ticks, lice, and fleas, many species have disease‑avoidance adaptations that result in them actively staying away from those that seem ill to prevent the spread of a potentially infectious disease. In the larger natural world, the fact that an animal will cut bait and run when disease strikes their kin is preordained — and if we follow evolutionary logic, we might expect humans to do the same. Rational choice theory, or the idea that humans are rational beings who exercise free will and are in control of their decisions, would likewise expect humans to avoid risks — in this case, the risk of contracting an illness — that are not in their self‑interest. Similarly, if we assume that the purpose of romantic love is to ensure the transmission of our genes via reproduction, we might expect humans to abandon a partner who is too sick to conceive or may not live long enough to have children. This behavior would be consistent with a phenomenon biologists sometimes call the Concorde fallacy (named after the Concorde, a British‑French supersonic passenger plane whose production costs famously far exceeded the original budget), which holds that individuals shouldn’t continue to invest in a sunk cost and should instead reallocate resources toward new opportunities. But in matters of human love, the rules don’t always apply. It is precisely because of the intense power of romantic bonds that we do things for our partners and for our relationships that are unlike what theories of the natural world and other behavioral science models would typically predict. In other words, it is a consequence of our intimate instincts that humans don’t abandon their pair bonds lightly. Our commitments to our loved ones, through thick and thin, are truly remarkable. To live and die for love is not what makes us human per se, but it is one of the most striking hallmarks of our humanity. A philosopher friend has teasingly asked me on more than one occasion: “Do you think we are human because we care so much, or do we care so much because we are human?” My answer is always consistent: both. THE POWER OF CARE Now more than ever — as we find ourselves navigating the dark, open, and uncharted waters of a human intimacy crisis, rising global environmental threats, pandemic instability, and an increasingly polarized political climate — understanding the science and power of caring may very well be critical to our own species’s survival. In the face of these existential threats to human health and well‑being, our thresholds for caring may ultimately define the next chapters of our relationships and our evolutionary legacy on this planet. Humans do something remarkable in our close relationships, which is to spell out explicitly the expectation that we will care for each other. We want someone in the trenches with us, someone who will tamp down the entirely natural urge to flee the scene when illness or adversity extracts its financial and psychological toll, and turn toward us instead. The natural world is unpredictable, and part of what we gain in the pair‑bonding deal is a partner to help us respond creatively to modern challenges, even if we no longer need to be kept on our toes about changes in food sources or predator threats. These intimate partnerships do more than simply help us withstand the vicissitudes of life: They help us heal from trauma, recover from illness, and maintain our mental health. That’s why I have long believed that in addition to prescribing medication and suggesting treatments, physicians of all kinds would do well to prescribe “relationship medicine:” tools that patients can use to maintain the health of their partnerships during times of illness. It might sound like odd advice coming from an oncologist, a cardiologist, or just your general practitioner, but I believe that investing in your relationship when you are ill or unwell is one of the best things you can do for your health. Intimacy helps to heal us and make us whole. That’s why it’s especially painful when an intimate connection is severed in times of illness. And yet, the capacity of humans to endure emotional hardship together is an important part of what makes us an intimate animal. Dr. Justin R. Garcia is an evolutionary biologist and sex and relationships researcher. He is Executive Director Senior Scientist at the Kinsey Institute, Ruth N. Halls Professor in the College of Arts and Sciences, and Adjunct Professor of Medicine at Indiana University, Bloomington. He also serves as Chief Scientific Advisor for dating company Match, providing expertise to the annual Singles in America study. Dr. Garcia has appeared on CNN, MSNBC, HBO, The Dr. Oz Show, Netflix, and National Geographic, and his research has been featured in outlets like The New York Times, The Wall Street Journal, USA Today, TIME, Cosmopolitan and Vanity Fair. While working on this book, he fell in love, and recently got married. The post Why humans live and die for love appeared first on Popular Science. ...read more read less