I know what you mean about it being both tragic and funny. And I admire your ability to be around your H when he is behaving so irrationally and unpleasantly and still feel and enact some compassion for him - I can't do that. I avoid my H like the plague when he's being difficult, which is no help for piecing.
As you're open to a reconciliation but prepared for divorce, perhaps what might help in this time is working on boundaries? Figuring out how you'd want to be in a marriage, and starting bringing that into your interactions. I'm not talking about increasing intimacy or closeness - your H can't do it and doesn't deserve it from you - but perhaps boundaries? I don't think if you were together you'd accept half of what you accept now and call it a healthy relationship.
It is a hard line to draw though. I am talking to myself as much as you, I think. I often think I moved too quickly with H and didn't emphasise - through solid boundaries and consistent behaviour - the kind of behaviour I would and wouldn't tolerate - for long enough - before we moved to R. He still pulls the odd move that it just so unacceptable to me. But I did accept it while we lived apart and he had no experience of having to deal with me refusing to tolerate it for long enough before he moved back in.
Perhaps you need to see what happens - if only for yourself - if you live your boundaries and refuse to act as an emotional crutch for someone who is being so unreasonable. You don't want to be in a marriage like that.
Edited to add: it's your comment 'let him sink' that made me think about all of this. I think he needs to sink. Hit rock bottom and then build himself back up. You don't want a marriage to man who you have to prop up. He's let you sink and you've - despite all the pain and abandonment and anger and uncertainty - flourished and you still are flourishing. Perhaps you are robbing him of that opportunity. You both need to be healthy and independent humans to be able to have a good marriage. If you are leaning in to stop him sinking - if he's expecting or needing that from you - then that fundamental shift that needs to take place isn't going to happen. And if he doesn't come back - if he drinks himself into getting sacked or a heart attack - well that will be sad and it won't be your fault, but in terms of the marriage you want - you won't be any further away from it than you are now.
