If he asks again just tell him you dont want to talk about it cause its an uncomfortable subject for you. Thats all you need to say and he should just leave it alone. If he dosen't leave the topic alone, just keep giving him the same reply and he should stop bugging you. I hate people like him!
you should just tell him you don't want to talk about it b/c you don't want the whole thing to turn into a major soap opera, and that you really should never have said anything in the first place and only did so b/c you were drunk, and hopefully he can relate.
most definately do not give him the information he is looking for. you never know what people's motives are, or if they might innocently let something slip.