My husband is convinced he showers every day, but it's really 1-2 months. He smells so bad I feel nauseous, but we share our bed. What can I do?

Will he let you help him in the shower? My late husband(who had vascular dementia)was very unsteady on his feet and needed help showering and would let me help him in it. He would sit on the shower bench and I would stand outside of it and wash him up best I could. I of course did get somewhat wet, but I didn't care as long as he was getting clean.
You will want to make sure that you have grab bars, a good bath mat, along with the shower bench so he feels safe when he gets in.
And if he won't let you help him, like suggested you can hire aides to come get him in.
And if all else fails they do make great body wipes in extra large and waterless shampoo and conditioner caps that you can order on Walmart.com or Amazon, that you can use to give him more of a sponge bath.
I had to eventually use both of those when my husband became bedridden and hospice was only coming twice a week to bathe him in the bed. They work great and are better than nothing.
I wish you well as I can't imagine having to sleep with or even be around someone that stinks so.

I would suggest you hire some homecare. Request a male CNA to help your husband shower. Some people are uncomfortable having a spouse or adult child helping them in such a way. I think aide care a couple of times a week could really benefit both you and your husband.

Take a shower with him

It sounds like it's time to hire a male aide to come in once or twice a week and bathe/shower him. If he refuses, either you leave the bed or he does.

Or you tell him outright: "No shower - no nookie." And I know you're probably *not* having nookie but he may still want nookie or think about nookie.

Move into the spare bedroom until he takes a shower. Rinse and repeat. You should not have to be nauseous sleeping next to such a stench. I understand about a dementia patient refusing to shower, and I also understand that if he values sleeping next to you, he'll agree to more often showers. If not, move out of the room.

Good luck

Take him out front and hose him down like a golden retriever.

Would the suggestion of a shower and back scrub together be appalling to him? I am afraid I don't have other ideas except just BEING there when he showers, and letting him know that you CAN smell him and it "ain't good". My brother, due to his Lewy's had lost his sense of smell and he hated deodorants, had convinced himself he didn't need then. I told him he did, in no uncertain terms. I think you can but do your best.