I agree. You should work on the reasons why you treated him that way, especially if you want to get back together or have healthy and happy relationships in the future.
Just make sure that your desire to get back with him isn't clouded by your heartbreak. Sometimes we push people away for a reason. Maybe you knew deep down that the relationship wasn't working or that you just weren't right for each other. You may miss the good things about the relationship or just the feeling of being in a relationship at all, but make sure you are remembering the bad times and the dull times, too. Don't delude yourself. You don't want to get back with him and then realize that it's a huge mistake. You also don't want to be pining for an illusion that never really existed. This will not do you any favors in future relationships.
I also agree with the other posters--don't mess with someone else's man. It will bite you in the butt. A guy who would break up with is girlfriend because his ex wanted him back is no guy you want. If he'd do it to her, he'd do it to you.
I think your best bet would be to work on yourself and move on with your life. You can't put your life on hold for a relationship that may never happen. Date other guys for a while. If your ex is single again sometime and you are too, then maybe you'll try again, but don't sit by the phone and let your life go by.
