Kingcanute, Not jumping in here to attack you, but a bit confused by this line in your post
Sounds like she is massivly insecure to me. A dog is not capable of thinking "ha ha look what I have done" THey can not do things deliberatly to ruin your day, they are canine not human!
You seem to be giving the dog human characteristics with one hand and taking them away with the other.
I think its worth remembering that dogs are pack animals, they interact with their pack in very complex ways (be it human or dog)and the hierachy(sp?) is very precise.
I had a male dog and my partner was never particularly fussed about him being well behaved. When I became pregnant with dd1 my dog decided that he was the alpha male, not my partner. He would scent mark incessently, climbing onto the sofa where I had been sitting, drooling and sh*tting. He would save urine at the end of a walk to annoint the house with as soon as he came in. I woke one night to find him defecating next to the bed. He became incredibly aggressive overnight, he attacked me with teeth.
We tried everything to keep him. Vet, behaviourist, cages, extra attention, exclusion, training by partner to reinforce who was alpha male.
In the end the vet the behaviourist, and the shelter that we got him from told us to have him put down, in their words - he is doing it on purpose, and you will never stop him.
We didn't have him put to sleep, we found him a new home and guess what the behaviour continued until he died 4 yrs later. He was being cared for by proffesional wildlifev sanctuary owners at their private sanctuary. They have many years of experience in these matters and agreed, the dog was doing it on purpose. If you bathed him he would roll in it
I would believe that with the age of this dog retraining should work, I would try the cage, method but ultimatey, with my dog he would just roll in it.
Sometimes I think dogs are more "human than we give them credit them for!!