Al Bundy wrote:

Is the male cat neutered? If not, you are fighting nature and the cat's
instinct.

Yeah, he is neutered. He was neutered at a young age, when we bought
him from the pet store. He's just always acted very "male" despite his
neutering. We've even tried putting him on female hormones (as in
birth control pills.) We've never been able to break the spraying
problem. When he passes, I have vowed never to get anther male cat.