Maybe I am doing it wrong. I feel like I am out of ideas.
Hi Trony and welcome to the family! I am so sorry you're going through this and I wish there was one magic phrase I could share that would make everything okay. Unfortunately, there's not because this is a process that both of you need to work through.
First off, is your husband in therapy at all? What's he doing to deal with the mental health aspects? And what about you- have you considered therapy to learn better ways to deal with this?
For your husband's part, he feels immense shame and frustration for struggling so often. He sees himself as a burden and instead of making adjustments, he gets so caught up in his own emotions that he lashes out at those closest to him (you).
So please understand, when he's blaming you for not making enough time, it's because you "make him feel better" when things are going well. But when he's off, and you don't magically fix things, then he blames you for something that has absolutely nothing at all to do with you.
The only person who can "fix" your husband is your husband. That's not your job or anyone else's. He has to want it though and be willing to work with a therapist until he's in a better position to deal with those overflowing feelings. Until then, there's nothing anyone can do...it has to start with him.
For the boundary part you mentioned, what have you tried? Hopefully you realize that boundaries are for you and you alone. For instance, if I decide that I'm not going to argue anymore and someone starts an argument, it's up to me to enact the proper boundary for myself. That could mean walking away. That could be staying silent. That could be changing the conversation entirely or showing compassion and asking what is really going on. Or I can yell back.
Regardless of what I do though, the boundary only works if I stick to it to avoid being in situations that I no longer wish to be in.
And when someone is used to arguing and complaining about everything, of course they're not going to like it when I refuse to participate. The boundary doesn't "fix things" and of course others push back. That's expected even when mental illness is not involved. Again, it's simply there for me- if you yell, I'm trying to calm you down and then walking away 100% of the time.
Does that make sense?