Sorry it's been a bit. Busy here. DD is graduating HS, and there will be family to contend with.
Oddly, it doesn't bother me as much as it probably should, or would, have in the past. Staying in my own lane as much as possible.
But I didn't want to leave you hanging... Sorry if this one ends up a bit short.
Oh heck yes! The lack of responsibility and accountability does feel like a deal breaker. The problem is, if you give them a pass, or buy the amnesia BS, you're setting the president that the pattern is acceptable - behave terribly, get away with it. Last time my H pulled the "I can't remember doing that" card, I told him that didn't matter, he is still responsible for his actions and needed to find a way to become responsible. Lost memories need to be addressed in counseling, not with the person who suffered as a result- and definitely not as their responsibility to make right! But it's pretty widely accepted that abuse amnesia is generally just a matter of convenience and self protection, not really lost memories.
Your H, like a lot of disordered people, is a champ at blame shifting. Once you learn to recognize that's what he's doing, you can just end the conversation right there. The key here isn't just good boundaries, but also being able to recognize it when it's happening and not let it go too far. Remember this : he has no interest in getting on the same page with you, so don't spin your wheels in place, thinking if you keep at it long enough, he'll start being more cooperative. In fact, you'll probably get a lot more interest and compliance from him if you back away and seem indifferent. He probably wants you to remain engaged for his own purposes.
Melody Beattie is the codependency expert. Even if you don't feel like you are codependent, there's a lot on her work that will teach you to detach and go about your life in a way that's much healthier for you. Good habits, I suppose.
Sadly, I think the reality for us both is that if some factors were different, we wouldn't let the door hit us in the backside on the way out. I've found it helpful to be very honest with myself about the reasons why I am still here- and then live into that. Living my own life as best as I can under unideal circumstances. Life will change for both of us at some point - by choice or by chance.