Having problems getting ova an ex?

my ex left me cus she fell in love with some other guy, i was deeply hurt so stayed away for a while, i gave her a call after 3 days and said about staying friends, big move on my part, then that night she was being very flirty with me and telling me she loves me and stuff, and she has been foning me alot, at times when she ain't got her bf around she is very flirty and tells me she loves me, but she is still going out with this other guy and has no plans on leaving him, i still have very strong feelings for her so when she tells me she cares it very difficult, i have tried to push her away many times to make things easier but she fones non-stop even sometimes crying on the fone about not wanting to lose me, it really doesn't help, i had an arguement with her recently about the situation and i told her to get lost and neva call me again, she has been calling but i been ignoring the calls, im started to feel the pressure now, its giving me a horrible feeling in my stomuch