We have cats, and he is probably doing it because you brought a new animal into the house. Even female cats will TRY mark their terrority. The male cat even though the new animal is a dog, is letting the new animal know that he is the Alpha male. If you haven't already you can try this stuff
http://www.petco.com/assets/product_...566301807C.jpg Unique enzyme solution works fast to permanently remove unwanted stains and odors like urine, feces, grass, blood, dirt, and more.
Totally eliminates urine odors.
Stops pets from returning to previously soiled areas.
Can be used on carpets, tile, furniture, pet beds, and clothing.
Safe for use around children and pets. This is a non-caustic, non-toxic, and non-flammable product.