Cat advice - neutered male “marking territory” in house

For anyone with cat experience, I could use advice! I got my first cat like 2.5 years ago when I got my own apartment, she was about a year old and litter box trained. She’s very well behaved and I never had any issues with her not using her litter box. We now live in a 4 bedroom house and my fiancé brought home a male kitten (both are fixed). We slowly gave them full reign shortly after the kitten was litter box trained.

Things were good until we noticed that cat accidents were happening (started when the kitten was 9 months ish). Just urine, typically in the basement. So we blocked off the basement. Then spare rooms, or random corners. We tested each cat, and it only happens when the male cat has free reign of the house (but he also hates not having full reign and will scream). Both have been tested for UTIs (negative) and I still see them both use the litter box regularly. I clean the boxes daily, and the male cat will literally watch me clean them and use it immediately after. I’m starting to think maybe he’s marking his territory? But we need this to STOP.

They have their own cat room where the litter boxes are kept, as well as food and hiding places. Both are super happy, healthy, and not stressed. My fiancé doesn’t clean after the cats, as he hates the smell, only I do. He won’t even go in the cat room. He blames me for the constant accidents saying that I must not be cleaning the cat room enough, but I clean it daily and it barely even smells like cats in there. (I’m very sensitive to smells- so believe me when I say I keep the cat room clean and it hardly smells). But does anyone know how I can get him to stop peeing/marking his scent??

We’re hopefully putting an offer in on a house and moving soon to a much nicer but smaller house. My fiancé has already told me (and i don’t blame him) if we can’t get him to stop before the move, he’s not coming. Most likely I’d take him to my aunt and uncles and he’d live in their heated barn as a barn cat. My cat (the one ive had for years) doesn’t have any issues, and I don’t want the kitten destroying the house.

**in advance, please no rude comments. I’ve been trying new strategies since this started and I’m at my wits end.

Edit: unplanned pregnancy, he would sooner get rid of the cats than change litter. Also, as I mentioned, I change the litter daily (twice if I have time in the mornings). The toxins in cat droppings take 1-5 days to form, so as long as I wear gloves and fully scrub down it’s safe enough. As for spritzing him with water, I would, however he only does it when we are not in the room, home, or at night when we’re sleeping. This doesn’t happen daily, but closer to every 1-2 weeks we’ll find a new spot.