You will need
  • - Internet
Remember all information you get about his ex-girlfriend. If it still means a lot to him, not to ignore it you can't. Find out how she lives, what's going on in her personal life, how deep the relationship was between her and your boyfriend. This does not necessary spy on girlfriend. Enough page in the social network, stories friends. But of course, the most important information for you, it was that the young man shares himself. So you can find out how he feels about the former now. Finding information should be a one-time. Please note all learned, draw conclusions and more not interested in her person.
If your guy and his ex girlfriend was a stormy relationship or a painful breakup, you need to be patient. If you really want to be with this person, don't rush things. The fact that he still is experiencing, the only evidence of its sincerity. Gradually you will feel that the young man remembers the old passion less and less. The alarm is to sound only when memories turn into an obsession, and you serve only as a temporary consolation.
Eliminate from your life everything that reminds you of your ex. This may be a particular music, where they were granted things. Remove the Association gradually but steadily.
Not categorically forbid any contact with ex-girlfriend, thereby restricting the freedom of the young person. Greet, if he admits that he saw her. However show you a little unpleasant for their meeting. If they have to cross at work or in a circle of mutual friends, a whole lot better if this will happen before your eyes, and not in secret.
Be yourself and never compare yourself to his ex-girlfriend. Show the young man your self-sufficiency, fill your life with interesting events, make new friends. And very soon the memories of the former will not cause your boy any emotion.