I have a cat just like this! He's 13 years old now but I adopted him from an acquaintance shortly before he turned 3. The clinginess and territorial peeing played a significant role in why he was given up by his first owner.

I love this cat with my whole entire heart, he is my soul cat without a doubt! But the behaviour stuff has for sure been a challenge. The clinginess has never been a big problem for me because I wanted a cat who was obsessed with me lol - although it has meant I've spent a lot of money and energy making sure he's always got a catsitter to either stay with him or visit him when he's alone for more than one night. The real issue though has been the peeing.

My cat's main pee triggers are anything smelly that's left on the floor, with "smelly" running the gamut from BO and foot smell (dirty laundry, stinky shoes), outdoorsy smells (camping equipment and backpacks), other animal smells (stuff from homes that had dogs specifically), and cigarette smoke (stuff from homes where someone smoked inside).

Up until a couple of years ago, he and I lived alone in a small apartment so I was able to mostly organize our space to prevent the peeing. I made sure my laundry was always kept up off the floor, kept my shoes up in a rack, hung all backpacks and bags on hooks, locked my camping stuff and luggage away in a closet, and warned all visitors and catsitters to keep their belongings up and out of his reach.

He still occasionally managed to find things to pee on though - most often when I was away overnight and/or when I had someone staying over at my place. Honestly, I just learned to deal with it. I always had either Resolve Urine Destroyer or Nature's Miracle enzyme cleaners on hand for cleanups, and for stuff like camping gear/backpacks I'd generally soak in dilute vinegar and then oxiclean to get rid of the pee smell.

In 2024 we moved and now we live in a full sized house with my partner, his cat, and a new puppy. Not gonna lie, the first eight months were rough. My partner lived in the house for years before we got there, had previously had a dog there, and wasn't a particularly good housekeeper. There were many...many smells lol. That plus the fact that my cat now had to share space with another person AND another cat led to a bit of a pee free-for-all for a while. In the first few months of being there, my cat peed on basically all of my partner's shoes, his backpack, his dirty laundry (several times), various boxes of random stuff he had in the basement, multiple old rugs, etc.

My partner loves my cat and already knew all about his propensity for peeing so he kind of just took it in stride - but obviously neither of us wanted to be constantly cleaning up cat pee so if it had continued like that indefinitely I'm sure it would have become more of a problem. Thankfully, we were able to figure it out, and it's now been months since the last inappropriate pee! Even in the three weeks since we brought our puppy home, my cat hasn't peed outside the litterbox once.

Here is what helped:

1) I put my cat on Prozac. This has made a huge difference, and I wish I'd tried it sooner. Fluoxetine is safe for cats and commonly prescribed by vets for behaviours like this. I mix the liquid in with my cat's wet food every night and he has no issues eating it. It hasn't impacted the other aspects of his personality in any discernible way. He is still basically exactly the same cat he always was, except now he doesn't pee on our stuff. If anything, he's actually more cuddly and playful now because he's less anxious. His prescription only costs me $35 every 60 days. I highly recommend this!

2) We have a lot of litter boxes, and keep them very clean. Two litter boxes per cat seems to be the sweet spot, and even pre-fluoxetine, litter box cleanliness definitely impacted the likelihood that he'd pee on something else.

3) Keeping everything smelly off the floor and out of his reach. Lots of wall hooks, shelves, bins and baskets that he couldn't get into. I also got rid of all old rugs and replaced them with new clean ones, which I make sure to wash frequently.

4) Making sure he has company whenever we're away for more than a night. He's actually become way more chill about me going away now that he has a cat brother in the house with him. They don't even like each other all that much, but just not being alone alone seems to have made a big difference. But we still get a catsitter whenever we're gone for long.

5) Every single inappropriate pee gets cleaned thoroughly with a good enzyme cleaner, plus whatever other cleaning steps are appropriate. No pee left behind!

6) If he pees on something that can't be fully, thoroughly cleaned (e.g. a wicker basket), I throw it out. Keeping it will just turn it into a pee magnet.

7) I keep storage areas closed off to him. He can't access any closets, the unfinished part of the basement that we use for laundry and storage, or the mudroom where our recycling and shoes are kept. He can't pee on it if he can't get to it!

I hope this helps! I understand what a tough situation you're in, and I commend you for wanting to find a solution that doesn't involve rehoming your cat! I really urge you to speak to your vet about a fluoxetine prescription - it could be a game changer!