Good insights. Interesting that when you quit looking for someone to make you whole is when you first met XH. It was a step toward independence and responsibility for your own happiness that perhaps opened the door to that R. The good news is that you took that step once, so you can certainly take it again. You are in a much better position to do so now too :-)
How was C?
Have you thought about going back to Al-anon or ACOA? You have to deal with your old stuff somewhere, and it seemed to be working for you. And, you have to deal with your new stuff somewhere. Working through the perceived betrayal with your old sponsor might help both of you, and would be more appropriate than continuing to try to work out those feelings with XH.