I'm trying to get over my recent "breakup".....HELP!!!?

I liked this guy who I thought liked me back. we saw each other every Wednesdays and weekends. He went on vacation and when he got back, he was suddenly ignoring me and eventually we didn't talk altogether. then, rumors started going around that him and my (now-ex) best friend were talking and hanging out alot........just like we were. On New Year's, I noticed he was on Facebook, so I sent him a message and it lead to me asking him if he had feelings for her. He replied "yes". it's been over 6 months since I found out about them, but i still care about him and can't seem to let him go. I see him all the time and it's gotten to the point where I almost hide from him, so I don't have to face what i still feel for him. I can't even think about dating other guys until i let go of him. What are some ways that can help me move on????