The motivation for men and women differs, he says with little hesitation.

"For men, it usually starts out as lust. Then it sometimes becomes love. For women, love usually comes first."

Affairs begin in the most innocuous instances. "All it takes is a concerned word from a co-worker on a bad day for initial feelings to develop," he says.

"After all, you're spending many hours in the office."

Offering a ride home, or rescuing a woman from the sexual advances of a client can also set her heart fluttering, he says.

And if you think your marriage needs to be in a bad state before the spouse starts straying, think again.

"Sometimes things can be going well, but then one party meets someone else who offers something the spouse cannot or does not want to offer, such as oral sex.

"There's a real potential for an affair to begin then."

And here's a tip for men - don't ignore your wife's need for attention after marriage.

"There was a woman who complained that while they were dating, her husband would go to great lengths to grope her breasts, get in a quickie , the works."

After marriage, however, she could strip naked and he would not take a second look, he says with chuckle.

Dissatisfied, some women look for love elsewhere.

"I know of some expatriate wives who get easily picked up at coffee joints, cafes, or even casinos. They get lonely because their husbands are at work all day, and the children are at school.

"But they're typically more discreet than the men, so they get caught less often," he says.

So is there a chance for marriages wrecked by infidelity to recover?

Sure, he says, but make sure the cheating is a one-off episode.

"Very often, one party is willing to forgive and forget. So the chances for reconciliation are high.

"But if you're going to cheat on your wife once every three months then obviously it won't work," he says.