At a young age, society trains our psyche to expect to meet the one, get married, have kids, and grow old together. Playground songs like “first comes love, then comes marriage, then comes baby in a baby carriage!” make love and relationships seem one-dimensional. Although in monogamous relationships commitment means no playing around, sometimes the inevitable happens — infidelity.

Cheating is a common occurrence in monogamous relationships. According to a study from the University of Chicago, 22 percent of married men and 15 percent of married women have cheated at least once. This all depends on one’s definition of cheating, but the majority does consider sexual intercourse or oral sex to be cheating, while other behaviors like kissing or sexual Webcamming fall into gray areas.

Infidelity can occur at any time in a relationship, with problems in the relationship being the main reason people cheat. However, it’s not always a sign that something is wrong in a relationship. Holly LaBarbera, a licensed marriage and family therapist in Fremont, Calif., told Medical Daily in an email, “Sometimes one partner meets someone with whom they fall in love. Sometimes one partner is unhappy themselves and a new relationship makes them feel alive and special in a way they haven't felt in a long time. Sometimes cheating has nothing to do with the other partner.”

Click "View Slideshow" for surprising facts about infidelity that every person in a relationship should know.