Need to get over a crush!!! Help Me!!

Abbegayle

So a couple of months ago I started likening this guy. He flirted with me all the time. So I thought he felt the same. Nope. We became great friends, but I never really stopped liking him. He a month ago told me he likes my BEST FRIEND! He tried for about a month but she rejected him. He still likes her alittle, he flirts with me all the time and I would give anything to not like him cuz I know he doesnt feel the same. How do I move on?