Skip to content

    Health & Sex

    Font Size
    A
    A
    A

    Why We Cheat

    Infidelity is a hot topic of conversation, but being faithful does have its merits.
    By
    WebMD Feature

    Sexual infidelity is one of humanity's great obsessions, perhaps second only to violence. We abhor it, yet we want to hear all about it, and some can't resist it. It's what has kept Jerry Springer on TV for the past 14 years and Greek mythology alive in the retelling for the past 3,000.

    In one story after another, mundane and epic, we are reminded of the emotional and social fallout of messing around. That's in addition to the scowls it gets from the world's biggest religions. Why, then, is monogamy so hard for so many?

    Recommended Related to Sex & Relationships

    The Starter Husband

    By Gretchen Voss You'd never buy a car without test-driving it first, right? So why settle into a lifelong marriage before trying one on for size? "I'm just really not ready to be committed like this." That's what Andi said to Tucker, her husband of 11 months, after she came home from a crazy day at work two years ago with an overwhelming urge to quit her marriage. Today. Right now. "This just isn't for me." She spoke stoically — no tears, no histrionics. She had been imagining this...

    Read the The Starter Husband article > >

    Perhaps for humans, monogamy does not come naturally, and biology predisposes us to seek multiple sex partners. That's what zoologist David Barash, PhD, and psychiatrist Judith Lipton, MD, argue in their book, The Myth of Monogamy: Fidelity and Infidelity in Animals and People. Virtually all animals, they say, are far from being 100% monogamous 100% of the time.

    "The only completely, fatalistically monogamous animal we've been able to identify is a tapeworm found in the intestines of fish," Lipton tells WebMD. That's because the male and female worms fuse together at the abdomen and never separate afterward.

    Other animals, including humans, are motivated to ensure their reproductive success not only by picking the highest quality mate they can get but also by taking others on the side.

    "The examples where monogamy is perceived to be the norm are generally facades when you actually do DNA testing and see who's sleeping with whom," Lipton says. She and Barash make a distinction between sexual fidelity and what they call "social monogamy." Even in animals that mate for life, like many birds do, DNA tests reveal that the offspring are often not related to the male of the pair.

    That is the case with people, too. Lipton says she was once contacted by a Canadian hospital, where doctors were running genetic tests to find out children's risks for inherited diseases. In about 10% of the samples, the children were not genetically related to the supposed father.

    But make no mistake: Lipton and Barash, who have been married to each other for 28 years, don't say that sexual fidelity is impossible or wrong because it is not natural, only that it takes some effort. "We human beings spend a large part of our lives learning to do unnatural things, like play the violin or type on a computer," Lipton says.

    1 | 2 | 3 | 4

    Today on WebMD

    couple not communicating
    How to tell when you're in one.
    couple face to face
    Get your love life back on track.
     
    couple having an argument
    Turn spats into solutions
    couple in argument
    When to call it quits.
     
    Life Cycle of a Penis
    Article
    HIV Myth Facts
    Slideshow
     
    How Healthy is Your Sex Life
    Quiz
    Couple in bed
    Video
     
    6 Tips For Teens
    Article
    Close-up of young man
    Article
     
    screening tests for men
    Slideshow
    HPV Vaccine Future
    Article