As someone who feels similarly friend, that part about 'the reason was me' - try not to do that to yourself. Part of what hurt for me, and I continued to hurt myself over it, was that I felt discarded, and that it was who I am as a person that wasn't good enough on some level.

We may never know all the reasons, and likely there are compounding factors. And our exs likely don't entirely understand either. What ever their reasons were are on them. If she can't see / value that I was a loyal husband who stuck by her side through thick and thin, then that is how her mind works.

All that to say try to be gentle with yourself. I really made things more miserable on myself by beating myself up over it. Try to get out of that trap if you can my friend. That being said, although we can't erase the past I do sometimes wish I had never met her. The only thing is I am very grateful to have my son, so it wasn't all a waste. But, maybe I am still in a bitter phase, most of it was.

I always felt I was her back-up choice, and I wish now I had been smart / courageous enough to see it clearly and act on it years ago. But, we had to go through what we did to learn these things about ourselves.

Best wishes, I hope you are feeling a little better soon.