But what are the chances of being happy again, after an affair? Or for rebuilding trust? For that matter, what does it even mean to rebuild trust after infidelity?  
The Erotic Equation
In 2006, couples therapist Esther Perel’s book Mating in Captivity caused a stir among sex and relationship therapists (and their clients) by suggesting that married sex was more difficult than most people realized. Drawing on the work of psychoanalyst Stephen Mitchell,3 she saw a fundamental contradiction at the heart of erotic marriage. 
Modern couples, she noted, were driven to satisfy two fundamentally opposite impulses—the yearning for safety and the longing for adventure. As she put it, “Reconciling the erotic and the domestic is not a problem to solve; it is a paradox to manage." Perhaps the reason conventional couples therapy is often helpless to revive sexless relationships is because the project to unite the erotic and the domestic was flawed from the start.
What saved Mating in Captivity from being a far gloomier book was the sheer force of Perel’s personality — exuberant, playful, with a European-born feel for the ironic. Hearing Perel speak was often so much fun that people tended to overlook the seriousness of her message. 
The advice she gave to people in erotically frustrated marriages was challenging: Allow yourself to feel more deeply the otherness of your partner. You never really possess each other. You just think you do.
That’s a difficult thing to keep in mind, but for some people, it can be more erotic. As she says, how can you desire what you already possess? Give up the illusion of possessing the other person, and eros might have a better chance.   
After the Affair
It's not surprising that Perel’s next book, The State of Affairs, would be about marital infidelity. Nothing makes you realize you don’t fully possess someone like finding out they’ve been sleeping with someone else. Infidelity surely ranks high on anyone’s list of the major causes of human misery. In the book, Perel herself makes an analogy to cancer. 
In recent years, she tells us, her practice has been exclusively devoted to couples affected by infidelity. So I was eager to hear what she had to say about whether and how couples can find happiness after an affair, or whether and how couples might learn to trust again.
 Karen Harms
Source: photo credit: Karen Harms
Since her previous book so often suggested acknowledging the “otherness” of your partner, I wondered what she might recommend to couples trying to heal from this ultimate act of otherness.
After an affair, according to Perel, couples that stay together fall into three categories: sufferers, builders, andexplorers.
For sufferers, the affair remains a black hole permanently fixed at the center of the relationship. What follows can be a lifetime of emotional pain.
Builders, relieved to have put it in the past, simply soldier on. The affair is sealed over, and nobody goes there again.
It’s the third category, the explorers, that most interests Perel. If I understand her correctly, they’re like the couples in Mating in Captivity who learned to draw erotic inspiration from each other’s "otherness," only more so, since there's no otherness quite like that of an unfaithful partner. 
It’s not easy, she notes, to be an explorer: You have to realize that every marriage is built on shifting sand, and that no relationship is entirely safe from jealousy or betrayal. But it’s the explorers, she contends, who emerge from the trauma most fully alive.
This is a challenging perspective, darker than I think most American readers will feel comfortable with. But she argues it with exceptional clarity, humor, and grace.
A Most Dangerous Game
The State of Affairs is full of stories of people who became more fully human as the result of an affair: The over-responsible married woman who discovers her inner rebellious child when she falls head over heels for a tattooed landscaper. The husband who is a dutiful provider both in and out of the bedroom, but finds that having paid a stripper for a lap dance, he can for the first time in his life simply receive.  
I think most readers would find all this to be well and good, as long as these people’s emotional growth left them better able to tolerate ordinary monogamy, but Perel has never been comfortable accepting such limits. Instead, she leaves her subjects free to figure out for themselves how to live their lives. We hear from all three points of the triangle: those who’ve secretly introduced a third person into the relationship; those who’ve later discovered the existence of a third; and, in one especially poignant chapter, those who have been the third.
Erotic love, she seems to say, is a dangerous game — and always will be. Accept that fact, and you’ll be more likely to recover from infidelity with your faith intact.
How much help will this book provide, for couples trying to find their way back together after an affair? Many readers will find it frustrating, since it contains no easy answers. But anyone affected by infidelity — i.e. most of us, in one way or another — will surely recognize themselves in it.
References
1. Parnass S: The Impact of Extramarital Relationships on the Continuation of Marriages. Journal of Sex and Marital Therapy 21: 100-115, 1995. 
2. Haltzman S: The Secrets of Surviving Infidelity. Baltimore: The Johns Hopkins University Press, 2013. 
3. Mitchell S A: Can Love Last? The Fate of Romance Over Time. New York: W. W. Norton, 2002.