How do you stop a cat from peeing in the house?

I have an older male cat, and he was spayed years ago. We’ve had him for over 10 years, so giving him away isn’t an option; I really, REALLY love my cat. We’ve had issues with him peeing on the floor before, but he stopped for a good while, and just recently, he picked up the habit again. How do I get him to stop?! I’ve heard people say, “when he pees, show him what he did and do something he doesn’t like- eventually he will stop”. My cat, like most cats, HATES water. Should I put him in the tub and get him wet as punishment? This behavior has got to stop, and I am at my wit’s end; I am very desperate. Please help.