Welcome to the Board. I'm sorry for what has brought you here, and I'm sorry that you're suffering so.
So, how do you move on? The answer is, at once, easy and difficult.
The first thing you have to do is decide that you're done, and you have to hold firm to that decision. And that's going to be difficult. You're still going to think about him. You're still going to miss him. You'll be tempted to reach out to him. But if you do, you need to understand that you're setting yourself back. If there's one thing I've learned about moving on from an addict, it's that there are times in this life where we're going to emotionally suffer. And we have to ride it out. Some days are easier than others. What's important, though, is that even if you don't feel like it, you need to go through the day-to-day motions in your life.
If you do this, one good day turns into two good days. Then two good days turns into three good days. Occasionally, you'll have a bad day. The deal that you have to cut with yourself is to accept that's how you feel at that moment on that day, and just because you feel that today doesn't mean you'll feel that tomorrow.
Anyways...about seven months after I broke up with my then AGF, I posted this:
http://www.soberrecovery.com/forums/...up-addict.html
Read it. See if any of it resonates with you. Keep posting, keep reaching out, and keep pushing forward. You'll get through this, in time.