Mom thinks I'm her husband on occasion. How do I deal with this?

Yes she is living with us and yes I am married to my current wife for 16 years. She and my mom had a great relationship before this. She will give my wife the occasional stink-eye, but she hasn't been actively nasty to her....yet.

I do resemble and sound like my dad. I recently went to her house to get some of her stuff and found a photo album from back when they were teenagers thru me graduating from high school. That really did the job distracting her and making her accept the truth. I also got some family pictures and hung them on the walls in her room. She's been good the last few days. When she's not like that, she's actually pretty chill. She broke her hip in July (the anesthesia from the surgery is what kicked off the dementia) and the surgery and following 4 months of therapy did little good, so she can't walk, so we don't have a wanderer. We put an alarm on her bed and a bedrail so she can't get up without us knowing and coming to help her.

I know it's not going to get easier and I really appreciate the input.

I had the same situation with my mother-in-law. My husband and & I brought his mother to live with us after his father passed away. She has been my MIL for 24 years, and have always had a great relationship. It wasn't long before she started to see her son as her husband. You don't mention if she lives with you or if you are married. If you are, how is your wife being treated by your mother? You can guess how mine did, I was the other woman. Having her in our home was a nightmare. I was cussed at, spit at, she would come in our bedroom in the middle of the night, turn on the lights and start hitting my husband. We would call her "Mom" over and over hoping she's snap back, show her pictures of the four of us together which should have proven that "Look Mom, here we all are together at Christmas, birthdays, etc" but absolutely nothing worked. Getting her out of the intimate setting of our home did. She doesn't see us holding hands, doing chores together, and yes my husband kissing me would enrage her. Her doctors tried different medications, nothing worked. I'm sorry for your situation as people don't think about those kind of things when taking care of a parent. I know we never did or we would have never brought her into our home. It was a mistake for all parties involved. As much as it hurt us, I know it hurt her much more as she was the one agonizing over her "husband" being with someone else.

Horrendous, I really feel for you.

I'm sure you already know this very well but I think it's worth saying anyway: you probably look and sound exactly like your father of thirty or forty years ago. She doesn't just think you're her husband. She is absolutely certain and convinced of it.

Do you have any photos of him around the age you are now?

Amazon - that is super awkward for you. I hope someone here has experience with this type of situation and offers suggestions.

Do you resemble your mom's husband? Is he your dad, too?
Just brainstorming here...Maybe, use COVID excuse, and put on a mask, so she can't see your face well.

How about trying actively to distract her with something else? Oh, look ma, there's a big moon outside. Or, look at the big fire on TV, etc.

I hope you'll get more suggestions.