You fool, the curse wants you to experience a one night stand. You need to find a douche who will leave you out of nowhere without giving a shit. So long as your friend sticks around, the curse breaking conditions have not been met. What you need is bestie to dump your ass. Unfortunately, since he doesn't seem to have much luck with other girls, he's unlikely to do that.
@Kilerog I've often felt the real catch in that kind of curse would be if its about the emotions. Find, guy, sleep with guy, guy runs if you don't feel the hurt of a girl at a guy doing that it doesn't count. It has to be a genuine betrayal meaning to turn back you had to reach a point where you don't really want to and are hoping you found mister right. So either you keep sleeping with guys for no effect or you get hurt by both the betrayal and by turning back into a guy yourself.