he still initiates abuse. Why do you think this is?
In psychology there is the concept of introject. What this means (to me) is the symbolic idea or image of an important love object that we carry with us. These objects become formative and enduring parts of our inner lives.
One challenge of growing up and away from our parents, is working out our relationship with these internalized "objects" on which our identities are based. For many of us, this process is fairly even and non-obvious. For others of us with traumatic or difficult life stories, or serious challenges in early adulthood, like mental illness (or both) this moving on in life can be conflictual and chaotic or blocked. Josh, like my son, (and me) fall into the latter category.
To Josh, you represent love and life. At the same time he is blocked in becoming a functional and integrated adult. That is because what he has to integrate feels impossibly difficult. So when he is blocked he projects this difficulty on to you. He has labeled you as the source of the problem. (Not the real you, but the introject of you. There is a kernel of truth here, because he's having a hard time working through his love for you, specifically the introject, in an adult way.) This is unfair. It is unhelpful. But it helps him feel less horrible, by projecting this "bad" onto you, rather than inside him.
In the short run, this helps him feel better. It handles his desire to be independent of you. It puts the problem outside himself into you. That's why he keeps returning to this.
If you push him in a way that makes him feel uncomfortable, that's why he has to turn on the rejection. It is like an equilibrium process for him.
Your interests and his are the same, as I see it. That he gradually no longer needs to use this as a coping mechanism. And that he can gradually find a way to make peace inside himself and with his life story.
Your task is the same. You (and I) need our sons to make sense of our own life stories. I will speak for myself. I feel lack, bereft, missing parts without my son, and without him loving me, and representing to me that my life has had meaning.
This is wrong. I need to find meaning in my life story myself. Not through my son.