My name is Jack-Jack!

Jack-Jack is a loving and sweet boy.
He enjoys drinking from the bathroom faucet and sleeping in cool, dark spaces. He doesn’t like to be held, but he loves to be pet and especially loves his chin and the top of his head scratched. He gives head-butts while I’m sitting on the potty to get me to turn on the water for him.
We have had him since he was 8 weeks old. It’s breaking my heart to have to do this.
He is spraying and marking in our new home. My son and his gf live with us. They have two large dogs and two cats. Jack-Jack doesn’t like big dogs. We have tried putting him on Prozac, pheromone collars and sprays, changing the litter, changing litter boxes, adding cat trees, and more. Nothing has worked. He has ruined our floors. I don’t know what else to do.
Jack-Jack would do best in a family where he is the ONLY pet, or in a family WITHOUT dogs.
He has a sensitive stomach so he eats Purina One Sensitive Skin and Stomach.