I agree that neutering will improve his behavior. (Unless he's neutered already.) I've always owned males, and after they were neutered, they stopped marking in the house.
I've heard many people say that once they start marking, even neutering doesn't help. But honestly, that has not been my experience.
Other than that, belly bands are the way to go when you can't watch him.
__________________  Snickers & Baxter Until one has loved an animal, part of their soul remains unawakened. |