Is being 'just friends' OK after 'I do'?

One of my wife's best friends is a guy. He's rich, good-looking, single, and calls her every day. Your basic nightmare. My wife swears their relationship is platonic. "We're like brother and sister," she says. Recently, I asked her to stop talking to him so much. She agreed and he stopped calling. Now he text messages her three times a day!

I know in my heart my wife is telling the truth: I'm the love of her life and there's definitely no funny stuff going on between her and Moneybags McGee. But that still doesn't make me any less jealous. The whole situation raises the classic "When Harry Met Sally" question: Can men and women really be friends? The answer is "yes," of course, but it's a little more complicated when there's also a significant other in the equation. So, to help me (and you) make better sense of it all, I've come up with four fundamental truths about the F.O.S. (Friend of the Opposite Sex) that anyone in this situation must understand.

F.O.S. FACT No. 1: There will always be some sexual tension.

I don't care if the person in question is a 400-pound Neanderthal with a comb-over or a practicing nun -- if he's your good friend, then you're possibly attracted to him on some level. It's only natural to be attracted to those we love. I'm not saying that you're necessarily going to act on this interest -- in 9 out of 10 instances you won't -- but to deny you don't feel a thing for your F.O.S. is pure B.S. This is even more true for guys with a female F.O.S. Believe me, guys are much more lascivious. I've had a few really close girl friends in my life (unfortunately, I don't have any now to rub in my wife's face), and I confess I had little mini-crushes on all of them. I don't know if they felt the same way, but there were days I wanted to put a little tonic in my platonic, if you know what I mean.

F.O.S. FACT No. 2: They keep your partner on his or her toes.

Whether your partner will admit it or not, your F.O.S. definitely flashes across her radar screen. Even if it's only occasionally. Your partner will be curious, inquisitive _ maybe even a little suspicious of your pal's motives. But hey, maybe this isn't such a bad thing if it also causes her to be more attentive and interested in you. I must admit that my wife's friendship with Moneybags has caused me to be oddly competitive. She'll come back from lunch with him at an expensive restaurant, and I'll offer to take her out to an even fancier joint -- maybe even throw in theater tickets and some flowers, too. I'm not suggesting you use your friendship to make your lover jealous (he might be anyway, so why bother). I'm just pointing out that a platonic friendship often can have the bonus of snapping your lover out of his taking-you-for-granted stupor.

F.O.S. FACT No. 3: It can keep your relationship healthy.

I can't believe I'm admitting this, but everyone needs a platonic friend. It's somebody she can confide in about their problems and concerns, especially as they pertain to the opposite sex. Some might try rebutting with the following argument: "But my spouse is my best friend. I tell him everything." A valid point, but it's also important to get an outsider's perspective on your love life. Who better than an F.O.S. -- a person who actually understands how the other side thinks? Some of the best advice I've ever received about relationships has come from an F.O.S., including the suggestion that I propose to my wife sooner rather than later. One caveat to all this: Before you open up to an F.O.S. about your love life, you need to be sure their intentions with you are above board. Otherwise, the advice you receive might not be in your best interest.

THE VERDICT: Having an F.O.S. can be completely healthy and natural.

We're adults, so raging high school hormones (should) be less of a problem. While you can't control the friend's emotions, you can control your reaction to them. Let's admit, there's bound to be that tiny bit of "If you weren't attracted, then..." Your rule of thumb for relating and socializing with your F.O.S. without enraging your mate should be: If you wouldn't want your partner doing it (shopping, hugging or something more "tonic") with his F.O.S., then don't do it with yours. And remember to use your power of opposite sex friendship for good -- like getting control of the remote.