H has surrendered....
For the past few months, I have tried a new tactic. As soon as H would start yelling, I would leave and not come back for a day or two.
For awhile, H would just get angrier and more verbally threatening, this is what is called an Extinction Burst. When the Non sets a Boundary, the mentally-unhealthy person will "kick it up a notch" hoping that you'll give up your boundary. I held firm.