if you two weren't together during this point then she had every right to do whatever she wished..i'm sure its hard for you to think about but it bothers everyone thinking about their partner with someone else...my boyfriend and my friend(well..friend/coworker whatever) messed around before he became involved with me..yea it kinda bugged me to think about it, but whatever, it was before he met me..what was he supposed to do?at the time they were sort of talking..it didn't work out, then i came around and me and him became serious..when i first found this out it kind of weirded me out more than anything but, honestly..you just gotta ask yourself if shes worth it and if you're going to be willing to get over this..if you dont want to lose this relationship, then you're just gonna have to get over it...