I went through that too, as so many of us have.
The think that kept me afloat in positive thoughts about it all was really knowing it was never my fault. It was a choice he made.
I made life my choice and we went in different directions.
2 years later I am happy. I think of him once in a while, but all I ever feel is sorry for him.
Healing only comes with time. Time makes us stronger. In the mean time, be very good to yourself.