How Marital Infidelity Became America's Last Sexual Taboo

As Americans increasingly embrace a range of behaviors, they're less and less permissive of cheating.

Universal Pictures

Having an affair is one of the most immoral things you can do, according to a new Gallup poll. As Eleanor Barkhorn reported last week, a survey of 1,535 American adults found that 91 percent considered extramarital infidelity to be morally wrong, a higher percentage than objected to human cloning, suicide, and polygamy. The poll aside, it's difficult to think of any other relatively common and technically legal (adulterous affairs are no longer subject to criminal sanction) practice of which more of us disapprove.

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While this same poll showed growing acceptance of divorce, pre-marital sex, and having babies out of wedlock, the 91 percent disapproval rate for cheating is nearly twice what it was 40 years ago, when similar surveys showed that only half of American adults believed that having an affair was always wrong. As political scientist John Sides notes in a recent detailed analysis of changing attitudes towards adultery, "Americans, and especially better educated Americans, have become less accepting of adultery with the passage of time." Pointing out the simultaneously growing acceptance for ending an unhappy union, Sides summarizes what he sees as our contemporary attitude: "If you're in an unhappy marriage, don't cheat. Just get divorced."

These dramatic shifts in attitudes towards both divorce and infidelity are driven by a changed but still seductive marriage ideal. The culture war over same-sex marriage may or may not be nearly over, but one thing is clear: So many people care about who can get married—and what constitutes a marriage—that the issue of marriage equality has become the defining civil rights cause of our era. If marriage no longer held much of a hold on our collective and individual imaginations, we wouldn't be having the impassioned arguments we're having in state capitals, in the Supreme Court, and at the family dinner table.

The polls show that a growing number of us want our fellow Americans to be able to marry whom they love, regardless of biological sex. Those same polls show that we also want to have the right to leave a miserable marriage as easily as possible. Those aren't inconsistent positions. They reflect the modern sense that marriage is primarily about individual happiness rather than making babies or ensuring communal stability. Everyone should be able to take their chance at the unique set of rewards we imagine that only marriage can offer; everyone should be able to leave if those rewards are not forthcoming.

The growing abhorrence of infidelity is linked to this more individualistic view of marriage. Just a few decades ago, divorce was scandalous; if your marriage came to an end you and your spouse were likely to face cruel gossip and painful social ostracism. The fear of the public humiliation that attended divorce kept people in unhappy marriages. That fear is gone, replaced by a growing anxiety about the more private humiliation of sexual betrayal. "I'd rather be left than lied to" is the prevailing sentiment that the polling reveals; it's not a stretch to suggest that the reverse would have been true just a few decades ago.

As Karen Swallow Prior wrote here at The Atlantic in March, young people are marrying later because they see marriage as a "capstone" to a well-ordered life rather than a "cornerstone" upon which to build. Whatever the wisdom of delaying first marriage for the sake of a richer set of life experiences as a singleton, there's little doubt that the "cornerstone" model builds in an expectation of difficulty that the "capstone" paradigm doesn't.

We expect couples who marry young to "struggle"—a common euphemism that encompasses everything from fights over money (of which there is almost invariably not enough) to extramarital flirtations and affairs. The cornerstone model presumes, optimistically, that men and women are transformed for the better by sticking it out through the "tough times" that everyone concedes will attend the marriage of the young, the poor, and the naïve. The expectation of struggle doesn't condone infidelity so much as it concedes its near-inevitability.

The "capstone" model presumes, as one of my friends puts it, that you only should get married "after you've got your shit together." Capstoners believe that marriage is something you enter into only after you've finished sowing your proverbial oats—and come into possession of the financial, emotional, and professional sophistication you'll need to blend your life with another person without becoming dangerously dependent upon them. The capstone model is much less forgiving of sexual betrayal because it presumes that those who finally get around to marrying should be mature enough to be both self-regulating and scrupulously honest. The increased unacceptability of adultery is linked to the rising age of first marriages. The evidence suggests, however, that the capstoners are more than a little naïve if they imagine that a rich set of premarital life experiences will serve as an inoculation against infidelity.

The same Gallup poll that found near-unanimous disapproval of cheating also found rising acceptance of many other non-traditional, consensual sexual relationships. The new ethical consensus that you can do whatever you like as long as you're not hurting anyone—and as long as you're being rigorously candid—reflects a thoroughly modern mix of tolerance and puritanical censoriousness. We've become more willing to embrace diverse models of sexual self-expression even as we've become ever more intolerant of hypocrisy and the human frailty that makes hypocrisy almost inevitable.

A Google search for "ethical non-monogamy" returns plenty of results about polyamory and open marriage. It also brings up sex columnist Dan Savage's notion of "monogamish" relationships, in which partners pledge enduring emotional commitment while enjoying "flings, affairs, three-ways, and swinging experiences." Even the monogamish life, however, is predicated on one key rule: telling the truth. As Savage argues persuasively, ethical non-monogamy can certainly lead to happiness. But non-monogamy and infidelity aren't synonyms—only the latter signifies betrayal. For non-monogamy's growing number of advocates, total candor is the non-negotiable admission price to liberation; "ethical dishonesty" remains an oxymoron.

Though it would be wrong to claim that American public opinion has ever embraced infidelity, there was a time within living memory when it was far from the most unacceptable of common human behaviors. That cheating has become our most despised sin reflects not only a changed marriage ideal, but a diverse moral universe in which dishonesty is the only vice about which we can all agree.