I'm so sorry you are struggling. That sounds so difficult.
Even though each of our situations is unique, there often seem to be relatable threads that run through them.
I definitely can identify with some of the things you have posted. It's a sucky place to be. Trying so hard with a spouse whose mood and mental health seems to shift unpredictably, and feeling like no matter how hard you try, you're fighting a losing battle.
RD mentioned his tendencies toward codependency. That's my main affliction. I just celebrated my third anniversary with codependents anonymous. I didn't even know what a codependent really was three years ago, so wonder if that could be something that you might relate to.
My perception of a codependent (at that time) was someone who loved and enabled an alcoholic to death. That is one way codependency manifests, but for someone like me, codependency is becoming so focused on the other person (or people) that I lost sight of who I was. For years, I nurtured my marriage, prioritized it and him (without much reciprocation), worried about his afflictions more than my own, and tried single-handedly to fix both him and our relationship. I was too "other" focused, I had stopped living my own life, and wasn't being cared for properly, not even by myself.
Relationships are 50/50 thing. The participants have to meet in the middle, and each has to give their fair share. And each has to know where that mid-line is, and not cross over it- not to be mean or selfish, but to keep the relationship healthy and balanced. I didn't even realize how far over the mid-line I was at that time. I just wanted to fix and rescue and have everything be okay again.
Do you relate to that? If so, learning about codependency might help you some.
I'm slowly rebuilding my sense of self, finding where I end and other people (like H) begin. It can be freeing, and even fun, finding yourself again.
Please take care of yourself, and post here if you just need to 'talk'.
Sending prayers and positive vibes your way.