I get the jerk thing a lot actually lol.
Allow me to give you a little more detail then. Because she flipped out after seeing me in the same room with my own ex a few months back, yes you read correctly (I didnt even talk to my ex because I didn't want to hurt her), I felt really bad about it even though I didn't do anything. Wanting something to happen between us, I told her that I was sorry, and we both agreed to be exclusive. We would have gone into a relationship but thats another story.
In the mean time she was already hitting on her ex, but I didn't say anything at the time since we were just friends with benefits. As time passed, feelings naturally developed, we both knew it, but still didn't want a relationship (long story), so we stayed friends with benefits. One night she completely ignored me and stayed with her ex. When I confronted her she told me that she ignored me intentionnally because her ex was feeling hurt and ignored.. WTF. I felt used. We had an argument, but I forgave her and continued our "relationship." So much for being exclusive and feelings. Oh yea her ex is still mad about her.
Which leads us to this break up, she pulled another "ignore Terpy so ex doesn't get hurt." I was shattered, so I excused myself and went home. She later accused me of ditching her. I couldn't take it anymore so I snapped.