I need to say that I feel sorry for this yorkie.. I would say that is the humans making him the way he is...

he needs to be rehomed.. before he is ruined completely...
My good god, I cannot imagine... I love my yorkies, not matter what,..and if you are so obsessed with cleanliness, then the sooner you rehome the better..
My heart is aching for this little guy.. there are people that do not have motherly instinct.. they do not have children, when they do,, the child suffers.. so I think your probably a great person, but just not a doggie person..
abuse does not always come in the form of physical.. it is also a mental abuse that just does not go away..
Seems like he is penned up too much, and alone to much.. maybe just finding a yter close to you, to take this baby in for a few weeks to just see if he is better with other dogs.. I would not suggest getting a mate for him.. for if that does not work, now you could have to that live full of anxiety..
Yorkies do not ever forget these things..