The first one admitted it. She got drunk (guy was trying to get her drunk to fuck her) She was actually a good girl. I was her first and she honestly was sorry.
Second one isn't proven, but I drove by her house and a guy was there (that she subsequently ended up dating after she and I broke up)
The third fucked God knows how many. Luckily only one of them was Man enough to tell me, even though it took a while for him too. All the guys that she dated in the last 3 years are on this site. Even before he did, I had my suspicions. (Girls like this crack me up, because she would get pissed after we broke up if she found out I was talking to someone else even though she was screwing our room mate).