First, don't assume it is not a urinary problem. "He" cats have very different uterine "plumbing" than "she" cats - and a UTI in a male can actually be life-threatening if there is blockage. Nothing to mess with - it is serious business for cats, but even more so for tom cats as they can become blocked more easily.

Please take kitty for a checkup just to be sure! Then you can work on the behavioral side.