Quit thinking she's the only one for you. If she was, it wouldn't be so difficult. There is no one magic person, destined to make you happy. I used to be fucked in the head like that. It's psychological and you probably should get help if you are that bad. I just got a self-help book which was enough to open my eyes. People who, as children, lose a parent or have a parent who is unavailable (alcoholic/divorced, whatever) are always trying to reconnect to that one special person (the bliss they experienced sucking their mommie's tittie) who, in reality, doesn't exist. Then they overwhelm every new lover with these obsessive desires to reconnect to what they didn't get as children. Any little slight, they perceive as rejection until their overwhelming fear of rejection becomes a self-fulfilling prophesy. They push the person away. Even when things are going great they will unconsciously start a fight with their lover because they are fixated with the struggle rather than their actual goal of finding that one perfect person (which does not exist).
Trust me, I've seen it in my cousins. One has a wife who he left twice and divorced for cheating on him twice (that he knows of). But he keeps going back with her. Why? Because he can't live with the rejection and must prove to himself that he is worthy of her. He can get a lot of girls too. His brother wants nothing to do with the girlfriend and newborn baby waiting at home for him, instead he'd rather sit in a corner bar and try to pick up some other girl. What decent girl will want that kind of baggage? But, you see, they will never be happy because they are programmed psychologically (as a result of their upbringing) not to be.
If you want the name of the self-help book, PM me.