applicable questions to ask yourself:
1. Are you bigger than her bf?
2. Is she using you to break up with him, only to dump you later? Or, is this more of a genuine type?
3. Is she.....skanky?
4. Why is she hanging around her bf still? If her bf is bigger, has more $$$$ or income potential, or is cooler than you ( you be the judge) she's gonna want to stay with him. If not, then you can definitely win, but it will probably take some time, with a slow kind of ....... process to win her over.
4. Is she living with her bf? I'm trying to figure out why she want to get into a developing relationship with somebody but not sever the old one. If she's living w/ him, mabey she knows that she'll need a place to stay once they break up.