A successful man who is put on a pedestal in his business life may feel that his wife does not appreciate or recognize his achievements or talents. After several years of marriage, she may have a career of her own, or concentrate most of her energy on raising children. Power can be a real aphrodisiac, says clinical psychologist Stephanie Newman in the "Psychology Today" article "Why Married Men Cheat." A wealthy, successful man may be faced with greater temptations than the average Joe, says psychologist David Frederick. The temptation of a young, adoring woman who is at his beck and call and boosts his ego may be too much to resist if the man feels his wife no longer sees lavishes him with the praise and recognition he craves.

After many years of marriage, a man may not be satisfied by his sex life. Work, children and all the mundane obligations of daily married life, like taking the trash out, cleaning the toilet or nagging the kids to do their chores, may get in the way of a couple's physical intimacy. His wife may not want to have sexual intercourse as often as he does. According to a study carried out by Loras College Psychologist Julia Omarzu, sex is the top motivating factor for infidelity within a marriage. Some 44 percent of married men have an affair because they want more sex and 38 percent because they want more satisfying sex, says the MSNCB.com survey.

Sex isn't always the key motivator behind infidelity. A married man may cheat on his wife if he feels she is not meeting his emotional needs, says Susan Krauss Whitbourne in the article, "The Eight Reasons that People Cheat on Their Partners." If a man has grown apart from his wife after a long marriage, he may look elsewhere for appreciation, support and encouragement. He wants a woman to desire, flatter and pay attention to him. An affair that combines a strong emotional bond with sexual intercourse is usually the most disruptive type, says the American Association for Marital and Family Therapy.

A married man may be bored and looking for something (or someone) to spice up his life. Some 40 percent of men cheat because they want variety, according to the MSNBC.com survey. A married man may use an affair to measure his sexual prowess, says Whitbourne. If he has had multiple affairs, he may be addicted to love, romance or sex, suggests the American Association for Marital and Family Therapy. The excitement of a new relationship or the high of sexual orgasm drives him to have affairs, even if he considers his marriage to be a happy one.