About a month ago my husband and I adopted a dog. He is neutered and housebroken. We had a cat already and took time to slowly introduce the cat and dog. However we are noticing that the dog is urine marking on things that the cat has scent on. For example, the couch that the cat sleeps on has been marked. The dog is NOT allowed on the couch but he is apparently getting on it while we are out and is marking. He also marks blankets that the cat sleeps on. Last night we put a freshly washed blanket down and the cat and dog both slept on it (at the same time) for about an hour. We then went to the grocery store and came back and the blanket had been peed on. I don't understand why he would pee where he sleeps, but that is what he is doing. I don't think it is seperation anxiety since he only does it on things that can be associated with the cat. But we can't catch him in the act since it doesn't happen when we are home. What can we do to stop this? The cat and dog seem to interact quite well except for this problem. I don't think it's a housebreaking issue since I have taken him out for a solid half hour filled with peeing and he has done it immediately afterwards. Please help!