Need advice on how to get rid of an ex girlfriend!?

Ok here's the deal. Last year almost to this very day I met this really beautiful Puerto Rican chick. She was pretty darn smart, seemed very sweet, strong willed, great sense of humor, I mean this girl had everything I would ever look for in a woman, and then some. Well as time went by we developed a very passionate relationship. I fell very much in love with this girl, and she "appeared" to be equally in love with me. Then something changed; she started to be more withdrawn, she stopped calling me as much, and even texting became like a chore for her. Then it happened. On my birthday of all days she sent me a damn text saying it was over and she had someone else (who happened to be a 17 year old boy), so it was such a humiliation, and blow to my ego. Well less than a month goes by and she is already seeing the flaws in her choices; so she comes back to me. Like a fool I accepted everything and took her back with open arms with the forgive and forget attitude. We dated for a few more months and everything seemed right on track; until she decided that she wanted a break. I just thought "Ok, well if this is how she wants it." but we kinda turned into friend's with benefits. Well this kinda sparked back into yet another full fledged relationship. This time it was extremely romantic, hot and heavy in every aspect. Then she left for Puerto Rico. She told me that she was going to PR for a while just to get centered, visit friends and family, all because she was feeling terrible and wanted to get back in touch with her roots and self. About 3 or so weeks into this vacation she pretty much told me that she didn't have feelings like that for me anymore and that I wasn't missed. I was frustrated, angry, and very heartbroken; but I got by and met someone and we've been trying to start something special. But here just a few days ago the ex has arrived back in North Carolina. She has contacted me and we've spoken. The PR vacation only made her feel worse. She had hooked up with some douche in a matter of days after me and her split the last time, and he used her like a hole in the mattress. Now she's back, and is wanting this buddy buddy bull$hit! I still love this girl and having her back in my life is affecting every aspect of my other relationships, with friends, family, and this new girl. PLEASE I'M BEGGING Y'ALL! Give me something that can help me get rid of this chick once and for all!