Boundaries are not just for our OWN behavior. A boundary, by definition, is a line of demarcation between someone else's behavior and ourselves, that -- if crossed -- carries consequences. "If you come home drunk again, I will ask you to leave" would be a more appropriate boundary than " . . . then I will sleep on the couch"; why should you inconvenience YOURSELF, based upon HIS poor behavior?
Also, there is nothing wrong with changing your mind about a previous agreement, if you decide it's not healthy for you. "I realize that was our agreement, but I have decided that this is no longer working for me and D" is all you need to say.
You seem to make a lot of excuses for your husband's poor behavior.
