Hi and welcome to SR
im sure youll find lots of support here. Im fairly new to the board myself but have made "some" progress since getting ideas/encouragement and some backup for me from others who have been/are where im at.
I dont know what program your ABF is working, mine is on the subutex and supposed to be doing SMART (but he didnt show up for his first session of a weeklong course so has to now wait for another offer).. i can relate to the side effects of the subutex, though AH outrightly denies these, the "on edge" when his dose starts to wear off, the stomach problems, the irritability etc. and what makes it worse, i am nothing like you and a pure reactor, so i react to his mood swings with mood swings of my own (but those are MY issues that i have to own).
I wish i could give you the answer.. but honestly, my AH's brain baffles me as much as your ABF's does yours. We too can go from harmlessly discussing where to get dinner from to a full blown, screaming, cursing arguement which invariably ends in AH storming off and "leaving me" (he knows that that triggers my ptsd and abandonment issues, so i think its cruel for him to play that card time and again)..
Maybe your ABF is relapsing and doesnt want you to witness this? maybe the subutex is playing up and his dose needs adjusting?
All i can say is, had i known what i know now, i would have focused on MYSELF a LONG time ago.. there are different approaches to dealing with an ASO... we had a long discussion about it on one of my recent posts and i found a "home" with a non 12step program, but lots of people find that 12 step programs really help them. In both approaches you learn to take care of yourself, to look after number one. For me, the bonus of the "alternative" method is that it actively works to help your SO into sobriety, you encourage the journey to being clean and play an active role if you wish to do that.. or you may choose that enough is enough and you are equipped with the tools to detach.
12 step programs are wonderful resource to get to know YOU better and to learn to improve YOUR life..
Whichever way you go, i would encourage you to get some help for YOU, maybe you can keep in touch with ABF's mom and sister?
Good luck