Miss Morgan: The only tried and true method I have ever found for getting over a boy quickly and painlessly is finding another one.
I know that could sound terrible, but believe me, it works, and it's not. After all, boys tend to hold a large, rather irritating power over our thoughts, and some of the only powers stronger than the woe-is-me, i-miss-him-so thoughts are the grand obsessions of a new crush.
Of course, that may not be what you want to hear, since most likely the reason you still think about him is because you still care about him. But considering the fact that from your question I get the feeling the "thing" would still be happening if you had your way, it leads me to believe he was responsible for ending it. Which probably means he isn't someone worth sticking around for anyway.