Basically, there are two things you can do: Either you let him bm around forever and swallow your anger and pride, or you just challenge him in a game on his terms (map, mu and so on) and beat the living shit out of him.
I encountered a similiar situation some time ago, when I started playing SC. A friend of mine would always 4- or 5-pool me and beat me although I actually was a better player than he was. He then would make fun of me, telling me how much better he was, until I could not take it anymore, practised hard against cheese strategies and owned him so hard, that he would never play SC with me again.