We can conjecture day and night about who and what is to blame for backsliding, but part of hooking up with your ex, and the attendant psychological and emotional baggage, is a comfort thing. Our old jeans are a hell of a lot easier to fit into than our new ones, and so is intercourse that doesn’t involve the vulnerable, "This is what I like, touch me here," period that a new relationship requires. New hook-ups take a frightening, stomach-churning amount of guesswork and investment, so ex-sex feels ideal for the risk-adverse. Need a quick lay? Call an ex, the boxed-cake-mix version of intimacy.

Comfort feeds reticence, and sex with an ex is the first verse of the “I’m not ready to move on” song. Recently, after a many-months-after-we-broke-up "visit" to an ex, he playfully dubbed me his “vintage luggage,” which I think he meant as a compliment. I imagined a well-worn case carried with him on short weekend jaunts (certainly nothing out-of-state). I was mildly offended at the time, but looking back, maybe that was all either of us was looking for: a reminder of an easier time. Sex with an ex is the relationship equivalent of moving back into your parents' basement. It’s cheap, you’re used to it, and it’s a quick move.

But what good does it really do to take a spin through the ol’ Rolodex? Often we end up self-sabotaging when we dally with recycled lovers. Nostalgia is a cold comfort, and feelings of intimacy and closeness can keep you from moving on and meeting someone else. (And trust me, it can happen to either party.) Sex with an ex can be like the mailer-daemon of good intentions, hurling all of our outreach right back to us.

Relationship patterns are patterns for a reason, and given that more than half of us are doing it, it looks like this one is here to stay (much like our exes). We’re never going to stop schtupping the people we’ve already been with, so maybe it’s time to recast the times when we fall into bed with a ghost from our past in a different light. Maybe we should think of these exes not as possible passages to previous relationships, but as nude conduits for self-exploration. At some point you know you have to pack up the vintage luggage and go back home, but for an instant, the vacation is gratifying, and if you’re lucky, you leave while there’s still enough time to find someone new.