The best advise I can give you is to let go of it and not try to win her back. It takes two to make a marriage work. My marriage went south after our daughter was born and I wanted to try to save it. My stbx was already seeing someone else. Point is if she's moved on then there really is nothing you can do about it I'm sorry to say. Just try to be as civil as possible for your daughter's sake. My hat is off to you for having so much time with your two year old.

Good luck.