Oh, hon, I know it's soo hard. Some days (well, most) it's excruciating to keep going through the motions. Some days it would be nice to be the crazy one.
But you're not crazy, and you can do hard things...you already are. And this will not last forever. One way or another, it will change. It may take a long time, but you won't be stuck here indefinitely.
It helps to get to a place where you're acting from a place of confidence and self- control. Where you are able to actively choose your actions as an expression of inner strength rather than fear. I remember reading that concept when I started with DB, and was mystified, but it came. Act as if until you get there.
Also, there are coping strategies for dealing with toxic people...those who change the rules every time you come close to complying with their impossible demands. Do a Google search and see if you come up with some new ways of dealing with his antics. Put your effort into what YOU can do, and you'll be okay.
It's okay to lose it. It's okay to stumble. Just keep getting up. A day at a time.