Good morning sweeti and welcome to SR!
From reading all of the posts, it seems there might be some information that we might not have and/or he might be reacting with this hardline 'ultimatum' for reasons that we dont know ( you havent maybe shared all of the peices of what his concerns are?).
Anyway, I know within the world of family support groups ( Alanon, Naranon etc etc) the concept of ' tough love' is strongly suggested to loved ones as a way of 'raising our bottom' helping us to face 'consequences' etc etc. It can come across as unloving or controlling when it is actually meant to allow our loved ones a way of taking care of self or setting boundaries.
Now I dont know if that has been advocated as an approach for your boyfriend, as I said there seems to be alot of peices of this puzzle missing for me. Regardless, keep doing YOU and your sobriety. That way, regardless of the direction this all goes, you'll be better equipped to deal with the outcome.
Coping with the loss of a relationship when we are in the bottle is always just a complete mess, never a pretty picture.
Keep coming back and sharing with us!
Be blessed.