Hi OP. Cat person here with 4 cats. So your husband doesn’t sound like a responsible pet owner.
Re litter trays, they should be scooped everyday and cleaned (thoroughly cleaned as in scrubbed clean with soap) every 2-3 days. You can get cheap cat litter but I’d recommend getting the more expensive stuff so the house doesn’t smell, you can also get litter tray liners and self cleaning litter trays that are enclosed, this may be an investment worth having if planning to have 2 of them as indoor cats. Can I just ask how that works? How do 2 get out but not the other 2? Our cat flap is a chip reading cat flap but only scans on the way in not on the way out so how do the other 2 not get out?
I’ve read through as much of the post as I can but not all. Can I ask how old the cats are? I don’t think you’ve answered that, it’s normal when they are kittens to have a couple of accidents but it shouldn’t take long for them to litter train.
This is my general list of how to be a responsible cat owner, maybe you should show it to him or get him to google it.
When first getting a kitten they should be adopted as there are millions of cats and not enough shelters to look after all the strays 😞
Once home they should be kept in a room with hard floor until litter trained so you can clean up their accidents hygienically.
Get them registered with a vet and vaccinated/fealed/wormed along with a general check up as soon as possible. Also get them insured.
Once 4/6 months old they should have their ops and microchips (they should not be allowed out before this!)
For me personally once a year old I let them out (hate litter trays so only have them
in the house when they are kittens) I have my garden cat proofed (google this as if he’s worried they will get lost then this may be a solution and mean you won’t need litter trays anymore)
What is also key is constant cleaning when you have animals (he needs to be willing to do this as they are his pets and you told him at the start they are his responsibility). I hoover every single day just because we have 4 and I mop every 2/3 days. We only have carpet in the bedrooms and most of the time the bedroom doors are closed.
I personally wouldn’t want the cats to be in a couple of rooms and not allowed to roam freely (within reason ie some doors closed) once older but if they were not litter trained I would absolutely keep them away from the rest of the house.
In regard to holidays for me the whole point of cats and not dogs is it’s so much easier. So when we go away we leave the cats at home, they have a water fountain and an electric feeder, the cat flap to come and go as they please & a little cat cam so we can check on them, I also get my mum or a neighbour to pop in once a day to check on them and give them some wet food. We close doors to living room, bathroom & bedrooms so they have access to kitchen/diner and the hallway landing and stairs.
It sounds like your husband has had 1 or 2 cats, not done the above and let them out to get pregnant and then kept some of the kittens and again hasn’t done the above to train them and now you and your house are suffering. If he cared about them as much as he says he does he wouldn’t have let his cat get pregnant once let alone twice.
Going forward it definitely wouldn’t be unreasonable for you to demand things change, especially since you are now pregnant, I have 4 kids too so I know what it’s like with cats around. Remember when your child is young never leave them unsupervised with the cats. He needs to litter train if keeping as indoor cats and until then they should be confined to a hard floor room or rooms. He needs to clean litter trays properly and regularly. Once they are trained he needs to have all the carpets cleaned. Once you’ve got past all of that life should be so much better and in future he needs to know it needs to be a joint decision to get any more pets.
I hope this helps and doesn’t come across as rude. This is just my opinions and what works for us so not everyone will agree with all of it. I hope it gets better for you.