Cheating girlfriend?

Last summer I found out that this guy had been chasing my gf for MONTHS on myspace. He was after her even when she was single and she blew him off constantly. She also blew him off while we were together. It's just that everytime he asked her out she would says she is busy instead of telling him she is taken. Her myspace said "in a relationship" but he didn't see it. Eventually she told him about me and he got mad because she never even gave him a chance and told her he was ready to hang out when she is. She went off about how she didn't want a bf when she met me and never wanted to see me after our first date, etc. Then at the end she stated that she is not sure how much longer we would be together is waiting for an answer from God. Keep in mind she blew him off even when single AND several months after I broke up with her she told him I thought she was cheating on me with him and how ridiculous she thinks it is because she just views him as a christian friend. But she lies to hide it