[...] In the face of the helplessness and vulnerability we feel at such moments, infidelity can be an act of defiance. Freud described eros as the life instinct, doing battle with thanatos, the death instinct.

Those same people may have previously felt tempted, but I wonder if it is the brusque confrontation with the brevity of life and its fragility that emboldens them to seize the day and act. Suddenly they are unwilling to settle for a life half-lived. “Is this all there is?” They hunger for more. Compromises that seemed reasonable yesterday become unbearable today. “Life is short, have an affair.” AshleyMadison.com’s infamous slogan may seem crude, but it is aptly targeted. Stories like this are so common that I now routinely ask my patients: “Have you suffered any losses, deaths, or tragedies in the past few years?”

Maybe it is death with a capital D, or maybe it is just the deadness that creeps up from dulling habit—whatever the case, I now see these affairs as a powerful antidote. “Love and Eros wake up the most tired person,”1 writes Italian sociologist Francesco Alberoni. The thirst for life triggered in such an encounter topples us with an irresistible force. It is often neither planned nor sought. The unexpected boost of erotic desire galvanizes us beyond the mundane, abruptly breaking the rhythm and the routine of the quotidian. Time slows down. The inexorable advance of age seems to lose its momentum. Familiar places take on fresh beauty. New places beckon to our reawakened curiosity. People report that every sense feels amplified—food tastes better, music never sounded so sweet, colors are more vivid.

The historian and essayist Pamela Haag has written a whole book about marriages like Danica and Stefan’s, which she calls “melancholy marriages.” Analyzing the plight of these “semi-happy couples,” she explains:

A marriage adds things to your life, and it also takes things away. Constancy kills joy; joy kills security; security kills desire; desire kills stability; stability kills lust. Something gives; some part of you recedes. It’s something you can live without, or it’s not. And maybe it’s hard to know before the marriage which part of the self is expendable . . . and which is part of your spirit.

It is a given that many people go outside to find things they cannot find at home. But what about those who go looking elsewhere for things they don’t really want at home? For some, their snail mail address is not an appropriate venue for the kinds of messy emotions associated with romantic passion or unbridled sex. As Mitchell suggests, it is much more risky to unleash those forces with the person upon whom we depend for so much. In such cases, people’s extramarital adventures are not motivated by a disregard for what they have at home; quite the contrary, they value it so much that they don’t want to tamper with it. They are loath to disturb the stability of their domestic lives with the intemperate energy of eros. They may want to escape the cozy nest temporarily, but they sure don’t want to lose it. Infidelity beckons as a neatly segmented solution: the risk and the rush in the lover’s bower; the comfort and closeness in the marital abode.

At least in theory, an affair solves the dilemma of reconciling security and adventure by promising both. In outsourcing the need for passion and risk to a third party, the unfaithful gets to transcend the tedium of domesticity without giving it up entirely. After all, the adulterous bed is not necessarily the place we want to take up residence—we just want the freedom to visit it when we choose. So long as we are successful in keeping the secret, there is a feeling that we can have it all. As sociologists Lise VanderVoort and Steve Duck write, “The transformative allure of an affair is heightened by this contradiction—everything changes yet nothing need change. An affair offers the seductive promise that both/and is possible—the either/or of monogamy can be defied.”

In other words, since time immemorial, women have put their emotional needs ahead of their erotic needs. She knows what turns her on, but she also knows what is more important than being turned on. She knows what she likes, and she knows what she needs. The choice is already made for her.

Stefan, understandably, has not deciphered this puzzle of the feminine senses. Like many men, when his wife withdrew, he concluded that she didn’t like sex. This leads us to another common misunderstanding that Meana’s work has highlighted: We interpret the lack of sexual interest as proof that women’s sexual drive is inherently less strong. Perhaps it would be more accurate to think that it is a drive that needs to be stoked more intensely and more imaginatively—and first and foremost by her, not only by her partner.

In the transition to marriage, too many women experience their sexuality as shifting from desire to duty. When it becomes something she should do, it no longer is something she wants to do. By contrast, when a woman has an affair, she brings a self-determination to her pleasure. What is activated in the affair is her will—she pursues her own satisfaction.

“Erotic silence” is the term psychotherapist and author Dalma Heyn uses to describe this predicament—an “unexpected, in-articulable deadening of pleasure and vitality”8 that happens to some women after they tie the knot. “A woman’s sexuality depends on her authenticity and self-nurturance,” she writes. Yet marriage and motherhood demand a level of selflessness that is at odds with the inherent selfishness of desire. Being responsible for others makes it harder for women to focus on their own needs, to feel spontaneous, sexually expressive, and carefree. For many, finding at home the kind of self-absorption that is essential to erotic pleasure proves a challenge. The burdens of caretaking are indeed a powerful anti-aphrodisiac.