How can you help an aging narcisistic parent with dementia?

Rocknrobin - you have come to the right forum. Look at some of the other stories on here - you are not alone and you are not the only one in this situation. YOU ARE NOT A BAD DAUGHTER. When you married, you and your husband became one and your first commitment is to your marriage. Your role as daughter is to help your mom get the care she needs not cave into her demands. It sounds like she is in the right place - try working with the staff to understand how she is doing and how they can help. If she has dementia, you likely won't be able to reason with her. Emphasize that you love her and yes you are sorry she is in AL, but that is where the best care is for her. And no, don't feel guilty. My guess is that she has consistently manipulated you all of her life using the guilt trip. And H*LL NO - if she abuses your husband, why on earth would she have the right to move in? Try disengaging someone - take fewer calls, see her a little less often to make your self stronger and more comfortable in your skin. You have nothing to feel bad about.

Have you ever spoken to the AL to see how mom is when you aren't there? She may be just fine. My grandmother was in a NH and all I heard was how awful it was. I walked in one day and observed her in the dining room holding court at her table and loving every minute of it. She got her nails done for the first time in her life and loved the activities.
You aren't dishonoring your mom in any way. Honoring her doesn't mean taking her verbal abuse and allowing her to treat your husband like a dog. A man and woman leaves their home to become one in marriage. Your husband comes first. You know in your heart that the AL is the best place for her and you. Don't go so often. Limit the trips out is this is upsetting her. Stand firm. You can do this.