Welcome AllieClaire!
I read your post and when you wrote he was 44, I thought - really!? It doesn't matter in a sense, he is choosing A over you. An aging decision for sure.
Doesn't fix your broken heart though. I'd go away on a girls weekend and rant & laugh about men. Can u move? I would imagine he'll drag a chit home to rub your nose in the break up?
You are adult child of an A? Have you worked on this at all? You saw all these red flags and kept talking commitment? Hey, not that I wouldn't do the same thing! I'd see them as a challenge.