When Harry Bent Sally Over The Hood Of The Car

My girlfriend's "best friend" is a straight guy. I trust that she THINKS he's just her friend. However, as a guy, I know that if he could hit it, he would. FYI, I'm not really a jealous or insecure person, and my guy friends complain about this same scenario, so this can't just be my stuff.

--Annoyed

There's a saying, "A true friend accepts who you are and helps you become who you can be" -- for example, a person who's naked in her true friend's bed, feeling really guilty about cheating on her boyfriend. Sorry to be less-than-reassuring, but you and your guy friends are right: For many men, the friend zone is a holding area where they wait to Mr. Sneaky back-massage their way into the sexfriend zone. In a study of 88 opposite-sex friendships by evolutionary psychologist April Bleske-Rechek, men were more attracted to their female friend than vice versa and more likely to assume she also had the hots for them -- a belief bearing little correspondence to how the woman actually felt. Women, on the other hand, tended to assume their male friend had only platonic intentions. And sure, some male friends are just looking out for their female friends -- but others do it in the way a hungry lion looks out for the limping gazelle. Bleske-Rechek's findings align with research by evolutionary psychologists Martie Haselton and David Buss suggesting that we evolved to make protective mistakes in perception -- erring in favor of whatever assumption would be least costly to our mating and survival interests. Men tend to overestimate women's attraction to them because they lose more by missing a possible mating opportunity than by making asses of themselves hitting on a woman who isn't interested (and, in fact, would eat a live pigeon to avoid having sex with them). Women, however, tend to underestimate men's interest, because they have a lot to lose from believing a cad will stick around to be a dad. You aren't without options here, though it's probably best to refrain from dusting off the old flintlock and challenging the guy to a duel at dawn. Showing jealousy suggests you have reason to feel threatened (like maybe he really is all that). Instead, simply be the better deal. Consistently show your girlfriend that you've got what women evolved to prioritize in men -- a willingness to invest time, energy, and resources -- like by really listening when she talks instead of uh-huhing her while blowing up alien invaders on your phone. Do this stuff not because you're afraid of losing her (which stinks of desperation) but because you haven't forgotten that you love her. And as a show of how secure you are, maybe even encourage her to hang with him -- that is, whenever she's all "Golly, it's been months since I spent the better part of an hour at the mall trying to decide between two slightly different vanilla-scented candles."