Well after like I said 15 yrs, it never changed for me. of course I know I've made too many mistakes over the years of allowing it to happen which only reinforced that the manipulation was working and therefore continued.

Obviously this is not easy for you due to your anxiety but the first thing that needs to happen is that you learn not to allow the manipulation to actually work on you. When he says "I'm done.. leaving.. etc" you need to be able to say. "Ok. I'm sorry you feel that way, let me know if you change your mind" showing him that you're strong and not letting this get the reaction he wants out of you. That's where you need to be if you're ever to make it clear that this threatening behavior is not ok.

Obviously you should both be in counseling but Idk if that will happen before he realizes that he's not going to get his way anymore or not.