How long were the two of you together?
How old are the two of you?
Why did the two of you break up?
What did you fight over?
What were some of the issues?
Basically you can't make a man commit to you if he doesn't want to. If he thinks that he can come in and out of your life and get what he wants and still be "friends" then of course he will do that, if you let him. The key is to stay busy, act like you don't need to be around him all the time, if he calls you, don't always answer, or be the first to get off the phone, telling him that you 'have something to do'. If he really cares about you then eventually he will start to wonder what's going on with you and why you are not showing the same interest you once showed and he will become the one who is chasing. Remember that you teach people how to treat you, no on can treat you badly without your permission and that's a fact.
I welcome your thoughts, let me know if you want to talk more.
Men are attracted to positive, successful, independent women with self esteem. People who have these qualities will attract many people. You can not call, you can tell him you'll call back and not call when you say your going to call, you can make dates and break them, you can give the impression that their might be someone else (without actually ever saying so) by sending yourself flowers or gifts that he will notice. Give him the impression that you don't really need him, and are able to be happy even if he wasn't there. All of this is considered game playing, can pique his interest and keep him off guard, and more importantly can backfire at any time. Also, most people play games until they get the person back and then they stop and the person might leave again anyway because the problem is usually much deeper than that.