Hello. This is my first post, and I really could use some help.

I have been dating this girl for 2 years now. I am 20 years old. We actually broke up like 3 months ago, but we talk constantly. I broke up with her. I have now realized that I truely love her, and I want to spend the rest of my life with her. She tells me that she really loves me, but she cannot deal with my controlling attributes anymore. I did not control her to be a bad person, I always thought of it as, i really love spending time with her. I didn't mean to do it in a bad way, but I guess it was bad what I had done. I honestly need her back, and she's so special to me. I love her terribly, and i'd do anything to have her again. I've told her I wanted to change, but I've said this before, and she's having a HARD time believeing me. I really want to change, but for some reason we end up in the same situation. I can't lose this girl... I want to change to be with her. I want to be less controlling, I don't know how to. Please help. How can I get her back, and how can i prove to her that I want to change?