Does anyone know what to do about this situation?

This could get confusing. It all started around late July when this girl (my future girlfriend) that I met started dating online with another guy. The girl and I talked every chance we got but I knew my limits. Then the girl and guy decided to meet in August. I was cool with it but I wasn't expecting what would happen next. The guy dumped her by email. I comforted her and later they got back together. I didn't mind because I believe in second chances. Then the day before she was leaving home to go to college, he dumps her by email again. I comforted her again. Then after a few weeks later, the girl and I decided to meet each other (we already started talking on the phone). We meet then we started dating each other. everything went fine before the ex-boyfriend decided to act like he didn't like her anymore. We both thought it was ok though but it would get worse. I at that time had a dream about another girl and told my girlfriend about it and we talked about it for a little while. Then I get online and find that her ex-boyfriend actually im'ed her and sounded like he wanted her back. My girlfriend and I got into a little argument about this when he im'ed me because of my feelings for another girl (which I got over). To make it worse, she was actually siding with him. That went on for a few more days before we made up. A week later, her and her ex had a fight and it looked like she didn't want to talk to him again. I felt a lot better after this. Then we both found out that he had feelings for another girl on a different forum. That made me happy that he wouldn't get involved with us again. It turned out I was wrong. Last week she said that she still had feelings for him and that made me jealous. She broke up with me two days later because she didn't know who she wanted. In the mean time I still love her and I don't want to make a decision that will hurt her for the rest of her life. He already ruined her life enough times. She says she has a stronger connection with him but worried that he may break up with her again if she goes back to him. Then she says she feels like she knows she is loved when she is with me. She also says that she feels secured and stable with me. We also have a good connection, maybe not as strong but close. I told her that I'll be happy if she is happy. What should she do about this situation? What should I do about this? I still love her to death.

Thanks to everyone who helps.

I just have some questions...are these relationships like in person are just over the net? I mean do you spend a lot of time with her in person? It kinda sounds like you don't, or with the other guy and her. Just wondering...

it's more of a internet relationship but we have met before. Her ex and her never met in person though.