I almost always agree with PG and this time is no exception. I just don't see the abuse here. I see behavior that I would never do as I don't want that level of information. If this is putting a strain on the relationship, which it appears to be, she should leave him if he does not stop but I don't think that makes him into a stalker or someone who is dangerous. Some people get off on their lovers having sex with others. Some get off by hearing about past experience. Some don't want any of that history and prefer a don't ask, don't tell policy (like in my case) - as long as I am comfortabel with the relationship now, and she with me, that's fine. However, just because he exhibits what I might call bizarre behavior, I just don't see the extreme threat that others do. This one is easy - tell him stop. If he doesn't, leave.