As Freud said, it's all about mother.
Or, as modern day psychologists point out, fidelity begins at home. Whether a son grows up to be a philanderer, depends a lot on the models he has for parents.
Just this week, a British psychiatrist blamed nannies for creating unfaithful husbands. In his new book, "An Unsolicited Gift," he describes the dueling affections at play when boys suckle on two metaphorical teats.
Dr. Dennis Friedman, a fellow of the Royal College of Psychiatrists, theorizes that having two female caregivers subconsciously introduces the child to the "other woman," and to the concept that more than one woman can meet his needs.
"As the British say, this is poppycock," said Michael Diamond, a Los Angeles psychologist specializing in male development and parenting. "It's too simplistic."
American experts say it doesn't matter who is the primary caregiver -- mother, father, grandmother, kibbutz or nanny -- sons need affection with boundaries, friendships with girls and permission to experiment with sex.
"Clinically speaking, infidelity happens much more when the male did not grow up with a healthy model of the relationship in front of him," said Diamond.
Many notorious adulterers didn't grow up with good parent models.
President John F. Kennedy and his brothers had a philandering father, Joseph Kennedy, who slept with starlets and then the son went on to have his own string of infidelities.
Bill Clinton, who used the Oval Office for his highly public affair with intern Monica Lewinsky, had no daddy and an abusive step-father while his mother married five times over.
Tiger Woods, with a cheat sheet as long as his tawdry tale, had too much daddy, a tyrannical father who pushed him in to the competitive world of golf, some say robbing the boy of his childhood.
Other highly public infidelities smacked of the entitlement that can come with money or power.
Eliot Spitzer, who as the "Love Gov" got caught with a New Jersey prostitute, had a classic rich boy resume and, some say, an elevated sense of hubris.
Nanny hater Friedman blames the absent mother, claiming that in adulthood Johnny may seek out the woman who changed his diapers and kissed his boo-boos better to get sexual gratification.
Psychologists don't discount the oedipal theories, especially the so-called Madonna-whore complex.
King of rock Elvis Presley reportedly slept with his young wife Priscilla only long enough to get her pregnant before turning to other women.
"The mother's overinvestment in little boy becomes so seductive to him that he feels that having sex with another woman is, at some level, incestuous," said Diamond.
Cheating: An American Obsession
The "obsession" with cheating seems to be an American phenomenon, according to Cindy Watts, who raised two sons while living an ex-patriot lifestyle in Asia.
Having sex with someone other than a spouse is often viewed as "an accepted fact" in countries like Japan and China, according to Watts.
"Most countries do not dwell on it at all, including many European countries," said Watts, who is 61 and now lives in Maine."So I think that men in America are put into a different expectation role when it comes to fidelity."
"The male species is programmed to biologically to spread their seed," she said. "Men with nurturing parents who feel free to talk about their sexual issues during adolescence and the threshold years [18-25] probably have a greater likelihood of being faithful."
As for her own sons, now in their 20s, Watts assumes that within their relationships with women they are honest about their needs.
"But I doubt that they are saints," she said. "Sex is a hugely complicated issue for boys."
Pepper Schwartz, a University of Washington sociologist who has written about sex and parenting, says boys who respect their mothers and sisters are more likely to understand women, "liking them as people, not as challenges."
"The more they see women as individuals, the more they see them as wanting the same thing as them, going horizontal and vertical," she said.
Raising sons to be faithful entails teaching them self-esteem and encouraging cross-sex friendships.
Once a man has an emotional relationship with a woman, a purely sexual one "seems empty," said Schwartz, author of the 2007 book, "Prime: Adventures and Advice on Sex, Love, and the Sensual Years.".
Sex should also never be taboo and recognize humans are sexual creatures, she said.
"There should be a period of time when someone can sow their wild oats and no one looks down on it," said Schwartz. "It's an adventure for young people and you acknowledge it and the let it run its course."
Tiger Woods might have benefitted from not having to live up to the "professional good guy" image, she said.
Schwartz said she knew of no research that points to any one thing that a mother can do that might actually promote infidelity.
As for Friedman, she is leery of a book that purports to be a study of human behavior without scientific evidence.
"It's very clever when you think about it," said Schwartz. "Of course everything is in the subconscious and it's hard to argue about because it's not measurable."
"This is the worst kind of research you can possibly do, to cherry-pick men who are non-monogamous who have a nanny in their life," said Schwartz. "There are 4,000 other reasons why men cheat."