I went through all this also, whole different story but similar feelings.
What you must realize is, this women is only telling you how perfect her new boyfriend is because she wants to get to you. She wants to make you jealous, angry and upset, fact is, right now she dose not care one single bit.
But chances are shill will be the one with regrets I promise you.
You have to disconnect I know its very hard to do. but focus on the positives, Think of just you. what made you happy all those years ago, what int rests you now, go and do something that you wouldn't normaly do. date other girls even as friends. you need a lot of healing, women are strange creatures at times lol, but they can help in situations like yours.
you have to try use your anger and pain and turn it into positive action.
That my friend is how you win in the end.
you become successful, and better than you used to be.