A muscular, middle-aged guy comes home with one of his friends. Together, they approach his hot wife, who happens to be lying on the couch and wearing the shortest dress she owns. She forgot to wear underwear. Again. The husband makes a proposition: Turns out, he's always fantasized about watching her have sex with another man. Would she consider doing so with his friend?


She gives the friend a once-over. He is even more muscular than her husband. His erection is nearly bursting out of his pants. She comments on its size, grins and asks her husband, "Are you sure this is what you want?" He nods, takes a seat and begins masturbating while his wife eagerly goes down on the other man. They proceed to have the hottest, loudest sex of her life right before her husband's eyes.

If you've ever browsed Xtube or PornHub, you have undoubtedly seen this and other so-called "cuckold" scenarios played out over and over again. But why would porn made by, and for, heterosexual guys so often depict men who take pleasure in letting other men have sex with their wives?


The answer, in part, is because there's a huge demand for it. In an age where pornographers are practically responding to viewers' demands in real-time, porn-consumers have made it clear that watching someone's wife bang a random guy is a top priority. When neuroscientists Ogi Ogas and Sai Gaddam analyzed the contents of a billion online search terms as research for their 2012 book A Billion Wicked Thoughts, they discovered that "cuckold porn" is second only to "youth" in heterosexual porn searches. (For the more literary-minded, a quick search for "cuckold erotica" on Amazon yields hundreds of books, including such clever titles as The Cuck Club and Lucky Cucky.)


But it's not just the market for cuckold content that bears out the trend. Believe it or not, guys on the internet constantly send me their fantasies about watching some stranger give it to their wife. "It turns me on to think about my wife having sex with another man," one guy wrote. "And not just OK sex, but wild, passionate, and very satisfying sex for her." Another wrote, "I wish I could take my wife to sex clubs so that I could watch her have sex with other men."

Allow me to explain. As a sexologist, I'm fascinated by what turns people on and why. For the past two years, I've invited visitors to my website to describe their most compelling sexual fantasies through an anonymous form. Not surprisingly, I get the obligatory desires for more traditional threesomes and orgies, not to mention a lot of interest in bondage, forced sex, cross-dressing and exhibitionism. There also have been more than a few Harry Potter-themed fantasies.


But more than anything, I've been inundated with tales from men eager to watch their wives or girlfriends take it from other guys. It's almost always watching without participating, and usually, it's important that the other guy have a bigger penis. Often, these guys aren't writing just to share their fantasy; they're anxious to find out if this desire is "normal" or healthy for an otherwise sexually fulfilled straight guy in a committed relationship.

Without delving into the issue of what it means for a fantasy to be "normal," my answer to these men, should I have to wager a professional opinion, is that it's perfectly fine to entertain this one. But not for the reasons you might expect.


From an evolutionary perspective, the idea that a guy would take pleasure from watching his wife with another man is counterintuitive. Historically, men have gone to great lengths to avoid being "cuckolded," or finding their wives impregnated by someone else. Not only does cuckoldry limit men's ability to "spread their seed," but it forces them to expend scarce resources raising someone else's kids. The fear of cuckoldry is thought to be a key factor that shaped how our male ancestors approached sexual relationships and, to this day, is considered by many scientists to be the reason men tend to get more jealous (often violently so) about their partners' sexual infidelity than women.

Of course, men have less to fear from cuckoldry today. Birth-control advances and paternity tests can put men's minds at ease. But cuckold fantasies aren't unique to the modern era. They were documented in the writings of Freud and others long before the pill was ever invented—so we know men today aren't into cuckoldry just because it has become "safe."


In the popular discourse, there's no shortage of theories on the origins of cuckold fantasies, or troilism in the vocabulary of psychologists. Columnist Dan Savage has advanced the notion that these fantasies are an eroticization of a man's anxiety that his wife will cheat. In other words, men cope with the threat of infidelity by turning the fear into something sexually arousing. More recently, journalist Anneli Rufus argued that troilists are just masochists who "revel in the psychological agony" of the humiliating situation.

But psychologists don't buy either argument. Eroticization is a strategy rarely taken with other fears. So why would it be so specific to cheating? Plus, while the troilism-as-masochism argument might apply in some cases, it proves weak when you consider that most cuckold fantasizers rarely desire other masochistic acts (like being whipped or flogged), and their interests tend to emerge in adulthood, unlike sadomasochists whose interests tend to develop in the early teenage years.


Increasingly, scientists favor a biological explanation based on a growing body of work on sperm competition. Research shows that when one woman mates with several men, those men can display behavioral and biological changes intended to increase their likelihood of fertilizing her egg—without even realizing it. For example, when men masturbate to porn featuring multiple men having sex with the same woman, their ejaculate contains more active sperm than it does when they beat off to an all-female threesome, according to a 2005 study of 52 men. Other research has found that men report thrusting faster and deeper during sex when they suspect their female partner has cheated, presumably as a way of displacing rival sperm. These findings suggest the provocative possibility that men are "wired" to find cuckold scenarios arousing because they promote behaviors that help their own sperm win a raging intra-vaginal sperm war.

Not everyone is convinced that sperm competition is the key, though. "I think of it as the 'King Bee Syndrome,'" David Ley, psychologist and author of Insatiable Wives: Women Who Stray and the Men Who Love Them, explained over e-mail. Many men he's encountered simply get off on the notion of other guys desiring their wives. They think to themselves, "'Look what a hot, sexy woman I've got' and how that reflects on the man's power," Ley says. "Displaying and sharing one's sexy wife is a status symbol."


That said, cuckold fantasies might have multiple motivations, and the factors involved might not be the same across individuals. Social and cultural norms likely play a role in shaping these fantasies, too. Indeed, internet search trends reveal that interest in cuckold porn has surged in the last decade, which, according to Ley, "reflects a complex interaction of female sexual and economic liberation, technology breaking down privacy and secrecy walls, changing marriages and more liberal sexual values." The internet has been instrumental in providing pornographic validation and a sexual outlet for men with cuckold fantasies; it also enables couples to easily recruit no-strings-attached third wheels to explore these fantasies in real life.


Based on my reading of the science, cuckold fantasies appear to be a normative male sexual desire. But should men act upon such fantasies? Ley warns that "these fantasies draw upon powerful emotions and social programming that shouldn't be treated casually or without careful thought." Bringing other people into your bed has the potential to affect your sex life and marriage in ways both good and bad after the action stops—a reality which porn videos have the luxury of avoiding.

Justin Lehmiller, PhD is a sex educator and researcher at Harvard University and author of The Psychology of Human Sexuality blog. Follow him on Twitter @JustinLehmiller.


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