Well, first of all you do sound like a wonderful and caring individual and most likely it doesn't have anything to do with you. However, I think that she really doesn't know what she want either, but right now she wants the other guy more then you, or she would be with you. It is very unfair of her to live you on the side like that, while she tries to figure out what she wants.
My advise is ... go out. Have a good time. You might meet a really nice girl who wants to be with you. Everyone wants a person to want them. You too need to date and see what is out there. Then if you do get back together you will not feel like she cheated on you or you missed out of something. And if you do not get back together, at least you will be developing some of your own independence. Good luck. Love can be tough, believe me, I know.