How do you get over a heartbreak?

This is a long one, but basically. How do you guys deal with a heartbreak?

Some years ago, my ex-wife left me for another guy. I was left with our 1.5 year old twin boys to raise.
I pulled through the betrayal with help from the people around me. My two boys are my pride and joy.
A year ago I dared venturing into the dating life and met a girl who was just everything I wanted. It was like being struck by fucking lightning, to quote the great Roy Kent. We dated for a year, but the distance between us, our jobs, and her feeling that she had to help me raise my boys, had her finding out that it was too much to handle. We had a long talk about it, and I agreed that our relationship had to end, if it really was taking such a toll on her.
We decided to stay friends because of our shared interests and social circles. This was like two months ago. I immediately started taking more care of myself. I watched what I ate, I went to the gym, I did what I wanted to do.

I felt that I had moved on, until I met her again yesterday and we talked like friends. She had definitely moved on and was doing great. She looked amazing and had all the time in the world for all the things she dreamed of doing.
But I couldn’t look at her without wanting to hold her. I fell in love with her all over again everytime she laughed at my stupid jokes.
And the heartbreak started all over again.