My guess us that Asshat does not wake up every morning trying to figure out how to aggravate Tesla.
He likely wakes up every morning trying to figure how to deal with the complex situation he has put himself in - living in an apartment with a young mother, baby girl and whatever other other animals that come and go. He has financial pressures to deal with and he has to work a lot of hours to keep up with that.
Mosely comes and goes all the time in Teslet's life. Unless I am missing something, there should be no real confusion here.
Letting Mosley stay at Tesla's house will be a treat for all involved and will give Asshat some self gratification.
I took on another Corgi last summer when the owners could not keep him and returned him to the people they got him from. I found out about it and offered to help take care of him. He was the brother of my Corgi.
Reggie came to stay with me every weekend and I showed that little guy all the love and attention I could.
A few weeks later, the owners said that I should keep that dog and just gave him to me. They knew he was better off with me.
Healing involves a continuous effort to let go of the past. Tesla has come a long way and I just adore her.
She is also a lot better off without Asshat. She did get a wonderful son out of that marriage.
Let him look like the good guy here and work to get Mosley back full time.