Hi OP. Just another MNer adding my name to the list of women with challenging mothers. The DARVO, the FOG, the gaslighting, sometimes it can feel unbearable and can push us to the edge of sanity.
Your experience with your DH isn't uncommon I don't think. People not from abusive backgrounds don't get it, growing up with nurturing or even just benign parents they can't understand the mindfuck of having a parent like this. And they can find it irritating and even toxic at times because they only hear offloading and don't realise its your cry for help. That's the double whammy of having a parent like this, you take the abuse from the parent but can be isolated in dealing with the fallout.
I finally went NC with my DM 7 years ago after 40 years of abuse, not only directly but having my name blackened through the family so I'd have nobody to turn to. I allowed her back in 2 years ago with very strict boundaries so she could get to know the DC (once they were old enough not to be too impressionable) but after getting her feet back under the table she has slowly reverted to her old tricks, pushed at my boundaries to see what she could get away with and escalated to her pre NC level so I had to put a stop to it, she's out of our lives again. Its sad, she's elderly but she can't change, the only thing thats changed is how I react (calmly walk away, no drama, don't give it any oxygen).
What made the difference was educating myself on how to deal with people like this, its hard at first because of the way we've been conditioned and the FOG but its possible and life changing. Realise that we can't change them, we can only change ourselves and developing healthy boundaries to protect our emotional health isn't selfish or cruel.
For practical help I can recommend CBT, counselling with someone impartial is really useful when struggling to get her out of your head. Also books I have read at various points and refer back to when needed:
Toxic Parents by Susan Forward,
A Woman in Your Own Right by Anne Dickson,
Surviving a Borderline Parent by Kimberley Roth,
Stop Walking on Eggshells by Paul Mason,
The Life Changing Magic of Not Giving a Fuck by Sarah Knight.
How to Have Impossible Conversations by Boghossian & Lindsay is also useful.
Something else that might help you straight away and won't cost a penny. When you have some time to yourself try to picture a big piece of glass in front of you, if you like slowly add details, maybe lettering, a fancy frame, is it bulletproof glass etc. Its your glass, make it appealing, pretty or threatening or however you like but focus on that glass being impenetrable. When you spend time with your DM, visualise your glass, watch her words and attitudes bounce off it, if your glass cracks fix it but don't let it shatter, she can't penetrate it. The more you do it the easier it is and IME it helps to deaden the impact.