I want to start off by apologizing that it took me a little bit to get back to you about this question. A mix of the crazy holiday season, and the fact that this is a tough question made me want to take more time to try to give you the best advice I could.
My first thought when it comes to this situation is that your friends are probably right. It really sounds like this guy is just kind of stringing you along. He's keeping you just close enough to enjoy the parts of you that he enjoys, while still not allowing you to get the parts of him that you want. My advice to you would be to probably distance yourself from him for a little while. I got the advice one time that if you continue to let him be your friend, but he doesn't let you be his girlfriend, then he is getting what he wants our of you while you're still searching for more. It's really not fair to you to keep putting yourself in that position. I think by distancing yourself from him it will help with a couple of things. It will really help you see if you care about him as much as you think, or if he's just another boy that you have a crush on. It will also help him to see how he feels about you. He might realize that he really misses you, or he might realize he's happy with his girlfriend and be okay with that. Lastly, it might help give you the opportunity to take a step back and look at the situation from an outside point of view, and really evaluate what you want.
Overall, I'm sure you deserve better than what this guy is giving you right now. Who is to say who can give that to you, but look out for yourself and make sure that all the guys around you are treating you with the respect that you deserve.
I hope this helps you out and continue to write if you have more questions,
Kevin