Thank you every one for such insightful answers. This definitely give me a lot to think about.
Snowmelt, I only fear losing her because I dont WANT to lose her. I want to be with her because we have had such a history and have gotten through so much together. She means the world to me and I can't imagine my life without her. We have spoken about what we would do if we ever broke up and she says that she would not be able to be even my friend. I guess what I'm afraid of is if we do break up, I will lose her completely and forever.