He just up and decided to bring her to our house to take care of her (without my permission and without discussing anything with me). She can’t walk, she has to be bathed and changed, and her meals have to be prepared. Most rest homes have refused her because of her terrible bad behavior toward the staff. I have expressed to him about the way I feel. He has ignored my feelings. I will not be helping him take care of her, because of how she has treated me.
What do you mean by: most rest homes have refused her because of her terrible bad behavior toward the staff? If they refused her, as in refused to admit her, she can't have had an opportunity to upset the staff. If more than one facility has asked her to leave because of abusive behaviors that's a different matter, but such behavior would have to be quite extreme for a step like this to go further than mutual agreement.
Anyway. What actually matters more is:
Do you like your husband and want to keep him? If so, you need to help him find more practical options for his mother and support him in withstanding emotional blackmail and the like. Don't refuse to contribute to MIL's care because all that will happen is that he will feel abandoned and trapped and stressed and he will become even more enmeshed with his horrible mother. If you lead or at least share the care, at least you'll have some control over what's going on (including, for example, sourcing outside help and deciding next steps).
If on the other hand your husband's ignoring of your feelings and wellbeing is all part of a pattern and you've already had enough of this marriage to last you... Is it time to walk?
Your no was not respected.
I would take that seriously.
I would schedule marriage counselling asap. It can really help to have a third party to help each of you to have your say & be heard.
In the meantime, ask him to move out. He can look after his Mother if he wishes in his own space.
Im assuming you two have been together long enough for long term marriage statutes to apply in a community state. In which case he can finance your living elsewhere while you work out what’s to be done with the house and with provisions that your half aren’t to be drained for mommy.
Be prepared when that time comes (and you know it will) by making a list of in-home care providers (aides to bathe her, somebody to cook for her or meals on wheels if he won't cook for her, etc.)that he can call to care for her and hand it to him when he asks. If you can go to another part of the house where she isn't, all the better. She doesn't sound like a nice person to be around.
He made this decision alone, he can handle it alone.