remember the reason why you broke up with him and don't do the back and forth thing.
You enjoy life to the fullest. Do something that corresponds with what you like, hang out and enjoy the scenery. Do something that you never thought you would(something good and constructive).
The human mind has the ability to fade bad memories. I think you are forgetting exactly why you broke up, and that is a good thing. Move on and be happy.
Focus on yourself and do the things you like to do,go shopping,visit friends and family. Don't sit around having a pity party for yourself,enjoy "Life" you only get "One" and you're wasted it on something you have "No" control over! Good Luck!
Keep on the path you chose. Don't look back. Never look back...
Don't worry you'll forget about him you just need time but if you regret your decision talk to him and try to be friends with him again!