How long were the two of you together?
Why did you split?
Howold are the two of you?
If he feels he has moved on, its going to be very hard to get him to see tings your way as right now it's probably a big matter of his pride. His feelings are probably hurt and he may even be thinking that you're out of his league. I would be consistent and a little persistent. Call him about once a week and say something to the effect of "oh I was going by so and so to (shop, eat, catch a movie, see some art, or whatever you know he would like to do) would you like to come with me?" He probably will say no at first, but as long as he's not already involved with another woman, your persistence will probably pay off and he will eventually accept an invite.
I hope this helps. I welcome your thoughts. Let me know if you want to talk more.