Don't feel too badly about things and think you are the only one it happens to because you are not. What you need to do first is to make sure you are able to handle things and by that I mean the disappointments that may come up when you feel you are really trying and not stress too much when they don't go your way.
See what your thoughts are on the points below:
1. Be patient
2. Communicate with your ex-wife but make it light and positive.
3. Don't put pressure on her to come back to you and try again.
4. Give her loads of space, you probably feel you have given her enough space.
5. Tidy yourself up, get a haircut, so she notices the change.
6. Chose your wardrobe wisely before you see her.
7. Be positive when you see her.
A relationship between two people does not just get switched off like a tap, there are still lasting memories, good times and bad. You must remember them yourself and wonder where it all went wrong. If you find it difficult still then you can always get help from a counsellor or even a close friend. Discuss this problem with them and see what their opinion is on the matter you don't have to take everything to heart just what you feel will be of help to you. One important key is communication keep that door open, if you feel that communication is only happening on your side then suggest a marriage counsellor.