How to get over him?

I’ve been in love with the same guy (Dan) since the seventh grade. So just about three years. I even liked him for and entire year while I was dating this other guy(Duke). Anyway, towards the end of me and Dukes relationship, Duke decided that he wanted to date my friend Chelsey. So he ended up kissing chelsey and so on. And at the time this was all going on Chelsey and Dan were dating. Well, Dan and I found out about what was going on with Duke and Chelsey and we were furious. So Dan ended up firguring out that I had been in love with him for a long time. So he and Chelsey broke up because of the Duke thing, and Dan told me that he liked me too, and we ended up making out. But being so stupid, I was too afraid to break up with Duke, and messed everything up with Dan. Me and Duke have been broken up for a year now, and I’m still in love with Dan. He says he doesn’t like me and never did, he said he just kissed me to get me to break up with Duke. Me and Dan are still best friends, but I still love him, and sometimes I can see that he still likes me a little. But he won’t go out with me, because I think that he thinks I might break his heart again. How do I get over him.