C.R.
I agree with Patricia, sounds like there may be more going on than the cat.
However, the cat is your cat and he knew it when you got married. I know that cats can be difficult when they are sick, but you said he is over that. Move the plants. Scoop the box everyday. Tell your hubby too bad! Old cats, especially ones that aren't "people cats" don't do well if they are re-homed.
All this said, if you think he will hurt the cat, that is another situation and the cat needs to be moved for his safety. Harming animals is a major red flag!
Good luck!