J used to tell me all the time, "we teach people how to treat us, Amber." Your roommate simply hasn't had a lesson in awhile and is thinking of you as the same person he used to know.

Be consistent in your responses to his come ons, and speak your points without hesitation. When he makes a suggestion, say you are not interested and why. Many people hate to hurt other's feelings (especially when the "other" is our friend who is doing us a favor) and resort to overexplaining thus making our own argument seem less valid.

For example, if he offers to have kinky sex you say, "Look Phillip (I am calling him Phillip, for the sake of this argument), I'm flattered but I'm in a place in my life where sex simply isn't that important to me. The relationships I want to pursue in the future involve a much more submissive man, which I don't see you as." Pretty straight forward. Rinse and repeat.

On the other hand, you might be inspired to say something like this, "look Phillip (still calling him Phillip), I'm flattered but I'm in a place in my life where sex simply isn't that important to me. I've had this surgery, you see, and I haven't really been interested since. It's not you, I was really happy with our relationship when we were together, I'm just not feeling quite the same. The relationships I want to pursue in the future involve a much more submissive man, which I don't see you as. You were always more Dominant, and I'm really more Domme myself now even though I'm still a little bit of a switch." Not as straight forward... You maybe think you've made him feel better, but all you're really done is give him at least three different "ins" to keep pursuing.

"Maybe it's her surgery," he'll think. "Hey, she still fings me attractive and like the stuff we did together, just not right this very second but she never did technically say 'no.'"

See what I mean? Hopefully? Maybe?