A few months ago I moved in with a new roommate who has 2 cats, and since my cat had lived alone for a year, he had some issues with it. He peed on several of my roommate's belongings in her closet. We've since dealt with that by keeping him out of her room most of the time and there haven't been any incidents for a few weeks now. But now in the past couple days my cat has started peeing on my bed, and I don't know what to do. He's never done that before. Keep in mind he's been neutered, and is litter trained. He's about about a year old. I plan to take him to a vet this weekend to see if it's a uti, but something tells me it's behavioral, and I don't know how to change a cat's behavior. Please help!
Also, I'm not sure if this is relevant, but the other cats use his litter box and vice versa, so I don't know if that could be the reason?