[Okami]

I've been having a male calico visit my house every day for the past 3 months. I give him food and spend a bit of time with him everytime he vists. Now Kai who is also male really doesn't like this visitor =(. He's started peeing around the house alot more ever since this other cat has been coming around. Now kai has been peeing in the house from time to time, but now it just seems.... excesive. Is this some kind of territorial thing? Can I do anything to stop it =( I don't want my whole house smelling like cat pee. He's got 3 litter boxes 1 on each floor always cleaned each day. I've tried lemon and citrus sprays on areas he's pee'd before but then he just moves to a different spot in the house! =( what can I do?