I feel that way about my ex-b's ex-girlfriend (very briefly until she dumped him) and then platonic friend. Like she keeps coming back a little at a time when she has nothing better to do, and now he's in Europe visiting her. At this point, it's almost better if something happens so it can then END. I am not sure how much she had to do with us breaking up. I do know that it effected us staying together. I am absolutely sure of that. I can't blame everything on her, our relationship had issues that were never brought up. But she's gone after other girls husbands, boyfriends, everything before. She won't last. If ex-b is gullible to get screwed over TWICE, then he needs to get that out of his system. It is very possible that he's been holding on to this just a little bit over the past several years.
