Ok, so Im dating this girl, we've been dating for a few months, and now she is starting to act a lot different. Every day she seems to get mad about a random thing, and then she will come back and say she is sorry and all that stuff. But now I'm starting to talk to a lot of her best friends and they all say the same things about her texting this guy and they are talking about dating. I asked her about it and she says it happened a long time ago, but I was talking to the guy she was texting and he says it just happened. Im pretty sure I should break up with her, but I am looking for some other opinions before I do it, so can you help?