Has your vet recommended any type of stress free prescription medication....like Amitriptyline (anti-depressant)? I say this because my vet suggested Amitriptyline on two occassions. Both times it was when we brought our dogs home. I separated my two cats and the dogs each time, and they had their safe haven space to get away from the dogs, however my older cat still seemed depressed or stressed...So, he started urinating out side of the litterbox. He didn't urinate anywhere else in the house, just outside. So, I had to keep paper there for a little while. I kept him on the medication for about 1 month, and then he started urinating back inside of the litterbox. Now, he is fine. I guess it took some getting used to the dogs in the house. My other cat had no problems with them dogs.