Wow, this is good. Really hard to read though because pretty much the exact same thing happened to me. My former girlfriend and I decided that it would be best to break up when she went off to college. I'm dating again, but I'll never forget her. Love really isn't something that fades. If he's worth missing at all, he'll remember you.
Let me start off by saying this poem's story is gret. There are some suggestions I have reguarding the writing style. It has been my experience that when you are dealing with almost any type of writing (poems especially) it is always best to have it appeal to all five senses. For instance the smell of his hair, skin, etc. This will make the writing much more intimate, getting your point across better.
P.S. It isn't my business but even if he is an ass, he'll most likely still miss having you around.