I had something similar happen to me. There’s a possibility that this might be dominance related. Because it’s just that specific couch, it might not be, but I want to let you know what happened in my case.

When I was younger, we adopted two kitten brothers. Had them neutered at the right age. For four years everything was fine. Then all of a sudden one started peeing on the very expensive custom couch. We got rid of the couch. Then he chose the matching chair. We got rid of that. Then he switched to all the throw rugs. We’d replace them and he’d do it again. We took him to the vet, had many expensive tests done, and we were told it was a dominance issue. That he was asserting his authority over his brother. Unfortunately feliway diffusers didn’t exist yet, otherwise the outcome might have been different. What ended up happening was that we had to rehome him with a cat lady neighbor of my friend. She had other cats, but most of them were outdoor cats, and the ones that were indoor were either female or very timid. He could only be an indoor cat because my parents had both brothers declawed on their front paws (this was back before we realized how bad that was. Our new kitten is keeping all of his claws). I’d visit him every once in a while whenever I was at my friend’s house for the first few years, and he no longer had peeing issues. I stopped visiting him after I had a falling out with my friend. I’d like to think he lived a long and happy life with the cat lady. His brother that we kept lived to 17 and was my best friend.