The boundaries are for our own sanity and safety .. it won’t stop them I don’t think …like you say he’s suffered some severe consequences and important life events and even then he won’t stop ..
I haven’t quite got out of stuff just yet but I am making baby steps…. Applying for new jobs, arranging days/weekends away with friends etc ..he knows now he won’t be number 1 in my life until hes earned it … And I’m very very close now to leaving and feel more calm and rational about it