The situation of the mentally  abusive spouse is in its self intolerable over time, if there are children involved, it quickly becomes unbearable.
I learned the hard way with a new supervisor, don't wait for the axe to fall, schedule an interview, ask what that boss wants & how does he/she expect me to deliver. Take obvious notes, showing your interest in the discussion. Then let the survival instincts start burning some of those reserve calories that have accumulated over the years...