First, marking establishes the boundaries and signposts of "home", the space that is secure for the family. That is why protective or insecure dogs and cats will mark upright objects (like a forest scout carving sign in tree trunk he passes by) or objects that are suddenly in a new place. I use an animal communicator for my own cats as well as for animal patients of mine, and they consistently tell me this.
He doesn't understand your reasons for objecting (although he can see you get upset), just as you don't understand his reasons for peeing, since the two of you come from radically different viewpoints on this. He is being protective of the family, to bolster security, and for that reason I can't imagine putting him in a doggy diaper to humiliate him. I feel that your reassurance will be much more helpful for him. The more he feels he is loved and safe, and the home is stable and secure, the less he will want to mark.
That said, homeopathy often helps permanently overcome this insecurity and the behavior that comes from it, but finding the right remedy will take into account Buddy's complete personality and physical health issues, so needs professional homeopathic consultation. It is also possible for you to find out directly from Buddy his reasoning in doing this--and also to communicate to him why you want him to stop--by consulting an animal communicator yourself. There is a web directory of animal communicators at:
http://www.animaltalk.net/consultlist.htmFinally, the best and also the cheapest substance I have found to COMPLETELY clean away animal smells from pee and other stuff is Oxyclean, or any of the new oxygen cleaners. I dissolve one scoop in hot water and use it to clean floors, spray directly on fabric items like sofas (dries without residue) or add to the washing machine. I have successfully rescued peed-upon fabric luggage, sofas, you name it.