I'm sure that when your ex presented the masterful idea that you--a recently broken up couple--should totally, you know, have sex sometime, he did so with utter nonchalance. You guys were enjoying the smoothies he picked up on his way over to watch America's Next Top Model with you, and he just casually muttered that if you wanted to slam uglies, he was "cool with that." He may even have been shrugging at the time.

Then he went home at masturbated to a photo of you before crying himself to sleep. Know this. It is man.

Your ex was being a dickbag, because people tend to do that when they get comfortable in a relationship, pushed things to the breaking point, and now regrets it. He wants to be friends with benefits because HE WANTS YOU TO GET BACK TOGETHER.

And not in a casual way. He wants to sleep inside of you and open up a bed and breakfast in the Adirondacks. This is because boys always immediately become improbably attracted to people who dump them. It's hard-wired into us, as a way to ensure that we never let our natural physical superiority get to our heads.

This is basically his purging process for the toxin that was your unhealthy relationship. I call it the Trainspotting Effect, because it's a lot like locking yourself in a room and going off heroin cold turkey: you cry a lot, you really want some heroin, and it's not over until you've shat the bed.

Given enough time, he may get over you and be able to be your friend again, but unless you want to entertain the idea of going out again, the sex thing is dead to you. At least, it is unless you want to switch your relationship status to "it's complicated."