I really, really understand what you mean. The A is not my fault but I did have faults that should have been addressed. For example, I never let him finish a sentence and I always had to be right. His main bugbear is our sex life which was pretty much non-existent.
Recently I asked him how come he could talk about issues now but he never raised them at the time? His answer was that I wouldn't listen. He is truly fixated in the past. If it comes up now, I tell him I understand etc but that the two of us were in the M and both of us are responsible for what happened. The DBing has made me look very closely at my behaviour and speech. I am effectively curbing all the negative and disrespectful ways of speaking and reacting. I am listening and validating as much as I can.
I'm so glad your H came back and that it's working out.