You make me think of one of my ex best friends... We were very close and I helped him through some very tough times. He caught feelings that I did not reciprocate. I loved him, but only as a brother. I ended up having to push him away because his hope of us ending up together was affecting our relationship and keeping him from finding someone else. He doesn't know how to let people go... He's a sweetheart and could easily get a girl, but he refuses to let any of them even get close to his heart. He almost refuses to notice their existence; because he refuses to think that I'm not "the one". Moral of the story: sometimes the best thing to do is move on. There are other people out there, you just have to open your eyes.
I don't know how helpful this was, but I hope that you either find her or find someone you care more for.