For almost everyone these days, a post-coital flop on an Ikea couch to watch reruns of Friends in your comfy green Hanes sweatpants alongside your pal in whom you just were is a discomfiting experience. Sure, there might be a vague feeling of reassurance, and probably the sex was fine— but you know it's just gonna get weird between you two. And you are scientifically correct! Odds on you, genius! According to a new study, written about in the Times today, Friends With Benefits relationships often end both the affair and the friendship. So next time you're drunk and horny and alone—sometime in the next 90 minutes, we're thinking—don't dive for your best friend. You should be having sex with your enemies.