How to move on?

Alright so here’s the situation..I’ve known this guy for almost six years and I’ve been crazy about him for about five. At first it was the crazy crush kind of love where I had butterflies every time we talked and I got nervous around him, etc. but now...

he is one of my best friends and we can have serious conversations or we can pick on each other relentlessly or we can just piss each other off to no end. The thing is we always come back from it and we are just great friends. We work together and other people we work with say that we act like an old married couple and when they say this, neither one of us really says anything because we know its true. He has been dating this girl for about two and a half years and she is great. I think she is a really good person, from what I’ve seen and I have no problem with her whatsoever. I do have a problem with their relationship though. Since they started dating they have both distanced themselves from all of their friends and only spend time with each other and their families. They’re both 21 and I think that its way too early in their lives to not have friends. He is a completely different person with me than he is with his girlfriend. I wouldn’t care so much about him if I didn’t think that he didn’t have any kind of feelings for me but he is extremely protective over me and to an extent, its unfair because he gets to have his life but anything I do, he has a comment for and he gets upset if I talk about other guys. I regret the last five years because my heart has been with him, even though he was in and out of the picture with school and stuff, and I’m not sure how to get past all of it so I can actually start having experiences and living my life without constantly thinking of what he may think. Any help?