I am 58 and have 5 siblings, I gave up riding rodeo and going to the nationals to take care of my dad in 2002. I stayed with my mother for 8 years so she wouldn't be alone till I finally moved to Utah and got back into horses. I was there for 7 years till she wanted me to come take care of her. I moved and am doing this but I need to also pay rent which is caring for her and now my uncle with stage 5 cancer plus all the housekeeping and buying the groceries. I have a 18 year old still home I am putting through college but now with 24/7 care have no income. I recently got married and although my mother is nice and sweet to his face she is constantly bickering to me that she is tired of supporting him. She doesn't support him he is paying our bills and buying the groceries to feed us all. We are going broke paying for everything to take care of the both of them.
You have done more than your bit for caring for your relatives. Retire from that role. This is your last chance at the mothering role, and you need to establish your new marriage relationship. This version of caregiving is not going well for you. Stop taking it.
It's also possible that your mom isn't thinking clearly. Maybe, she's under some delusion about your husband. Those are difficult to squelch. If her mental ability is declining, she might not be capable of sorting it out. I'd take note as to what it might be and then make my decision.
Oh, another thing. I found that with some seniors, if you tell them that someone said good things about them, it makes them feel good and they seem to improve their opinion of them. You might have to be creative to make that happen, but it couldn't hurt.