SWOT you are not Abandoning him! He is making the choice to not behave in a civilized fashion and respect your very reasonable boundaries. His choice, not your doing. You are still right where you have always been, when he chooses to behave in a civilized fashion.
You’re right, you can’t go into the spiral with him. All you can do is keep yourself strong so you’re still there for him when he is ready.
Hugs.