I think in the back of your mind you know you're better off without him. Listen to this little voice.
If it's already over it sounds like you've done what is right and necessary. Try to feel happy and secure in this thought.
The main thing you need to hold onto is that there is someone else out there for you who is going to take care of you, love you consistantly, challenge you in all the right ways, and you will find him (if he doesn't find you first).
I've been through some tough break ups. It took me a whole year to get over one guy. In the meantime I had started dating someone else but it took time to forgive him, move on and be happy.
Give yourself time, allow yourself to cry, and if you're sick of telling friends the same old story keep posting online or get yourself a diary. But take care of yourself, occupy yourself, keep him out of your thoughts as much as possible and eventually you won't have to try anymore.

Good luck and cheer up.