No marriage is exempt from adultery: its victims include princes and princesses, first ladies, celebrities and ordinary people. To talk about the issue, The Early Show turns to Brenda Shoshanna, a psychologist who is iVillage's "Relationship Saver" and the author of the book "Why Men Leave: And What Might Have Changed Their Minds".
On Friday, the "After I do" series examines what happens to a marriage when one spouse looses his or her job.
Shoshanna's advice to couples dealing with infidelity is to work on staying together.
"I do advise them not to run away from one another for many reasons. If you do, you'll run away with a lot of bleeding wounds, and it would be difficult to go on," she says.
An important factor to stay together is having a common cause, Shoshanna says. Organized religion may offer help for some couples, but those who don't have such support may find the road harder, she adds.
"Usually with a common cause, they can band point. But it is harder, because usually their friends tell them to split apart and that's the wrong advice," she says.
As for the affair itself, Shoshanna points out, the reesponsibility belongs to both parties.
"Often the man does feel his needs aren't being met and there's a lack of communication. But the responsibility lies upon two people. So the lack of communication isn't only one party's fault. And often men don't know their own needs, so it's hard to express them," she says.
That is not to say that infidelity does not occur to couples who have a good relationship, she adds.
"For some men, they compartmentalize love and sex. It is just sex. They don't even think of it as a betrayal. It's just fun fantasy life. Many men see sex and love as two separate things. Men can have sex without emotions," she explains.
In light of the recent Hollywood movie "Unfaithful," there's been a lot of talk about female infidelity. Shoshanna says husbands and wives cheat for different reasons.
"Men will cheat because it's part of the male ethos to get more conquests. And often it is just sex," she explains. "But when a woman cheats, it's because she's emotionally unsatisfied. They're usually looking for love, attention, affection, closeness, bonding. Very few women cheat just for sex and therefore when a woman is cheating, there's much more at stake in that situation,"
So what is there to do? Shoshanna says honesty is important.
"The thing that causes harm is the lie," she says. "Lies cut into the fabric of two people. Even if you think people don't know it, there's a level that they do know it. Lies take their toll. You're not really getting away with anything. And if you lie to people consistently, and they seem to keep believing the lie, on some level, you lose respect for that person."
Honesty is also what she recommends when talking about it with the children.
"We have to admit it, apologize and put a positive turn on it and explain to the children and the family and tell children you're sorry and will grow and learn about how to be fair to all," she says.
Shoshanna is also the author of "What He Can't Tell You...and Needs to Say: Intimate Conversations with Men" and "Zen Miracles: Finding Peace in an Insane World."