Analyze your relationship if the reason for your breakup was you, you have on yourself to work hard. Maybe it was your jealousy and mistrust? No surprise, then, that your guy is tired from the everlasting suspicion and chicanery, and found a more relaxed and confident girl who is not satisfied with the trivia scene. Increase your self-esteem and confidence in their own irresistibility. Confident girls have a special look and a special gait — become like this, and let him see how you've changed.
Try more of caught your ex eye, and preferably in "your" places — in the Park where you first kissed, the cafe where you went to dinner on the weekends. When your "random" meetings all around must remind him of the happy moments spent with you. Of course, you have to be "in full dress". It would be better if you change your image, perhaps even radically, to give him the illusion that he doesn't know yet. You must again become for him a mystery that he wanted you to solve.
Find out about the new girl your guy the best I can. Where she lives, learns or works, what motivates and where it goes. You should all be above her head and to always be a step ahead. She goes in for sports professionally? And you learn some new fashionable sports game, for example — floorball. Will do well at the competition and don't forget to invite to the match of his boyfriend with his new girlfriend she jealous.
Invite him to a meeting and openly admit that you still love him, but don't say that you want to bring back, say, "let's start again!"