In the movie Hitch, Will Smith plays a guy who wins fame as a relationship expert. In real life, Will is married to actress Jada Pinkett Smith. His philosophy on marriage in real life may remove him from the top of your marriage-consultant list. The Smiths, advocate what might be called therapeutic adultery—adultery within certain rules.

To begin with, there's the spousal notification rule. As Will explained to the New York Post, "In our marriage vows, we didn't say 'forsaking all others.' The vow we made was that you will never hear of something I did after the fact."

Then there's the spousal consent rule. "If it came down to it, " Will says, "then one (spouse) can say to the other, 'Look, I need to have sex with somebody. I'm not going to if you don't approve of it—but please approve of it."

While the Smiths have yet to actually test their theory, if Mr. Smith does follow through with an act of "therapeutic adultery," then his next leading role might be a real life drama called "Unhitched."