unless you're in a mutually agreed upon relationship of EXTREME honesty where you can both talk about anything without worrying about how it affects the other person...well, you just don't do that. i made that mistake in college, not even thinking when i was with a current girl about how stories about my ex would make them feel. i just thought of them as stories. believe me, i've learned my lesson...and if her talking about this kind of stuff is bothering you or making you feel insecure, then you have EVERY RIGHT to confront her about it and tell her to stop living in the past and just enjoy who she has now.