I think I'm in love with my best mate

But now what's come and like stabbed me in the brain? Well Cupid seems to have decided that I should fall for my best mate... who has a girlfriend. She doesn't go to our school and they've only been talking less than 2 months and dating 1 month. He talks to me about planning on having sex with her when he turns 16 and it actually like hurts me. But like I just dunno what to do!? I have no one to talk to about it because I don't want to tell anyone I like him. 

Someone talk to me?