Hey man, So sorry to hear how things are going. I know how hard it is to be in limbo and feel like you are the only one in the relationship at times. Do you get the sense she'll be back at some point? Or is she still talking divorce? Or just not talking and giving you the cold shoulder?
Either way you will be well served by honing your communication skills. You are in for lots of drama either way I'm afraid. I shudder to imagine what it'll be like if you do ultimately divorce and try to share custody and she is angry/vindictive. I hope that is not the case.
My fella is high functioning too. Doesn't fit all the criteria. Is a bit compulsive with spending at times, though I try to guide him towards being more careful when I can. Sometimes what I say is in one ear out the other though.
He is definitely overall much more appreciative though, but his cycles are much shorter. Bummer about this "princess" behavior. All that indulgence she's had is all she's known, so I imagine she is pretty resistant to boundaries and limit setting, and "no."
I imagine the tough part is that here you are trying to keep the door open on things and she isn't giving you any positive signals back and you are left to wonder am I really in a relationship at the moment and how do I go forward? Just keep taking it day by day until you feel ready to move things into another phase and organize your life in a new way whatever it may be.
And even if she comes back, with no sense of any responsibility for hurting you at all... .that is so hurtful.
On the other hand, it might help you to put aside at least some of the typical expectations and rules. Remember that she doesn't have the same tools you do and her mind simply doesn't have the capacity to recognize/feel emotions in the same clear way you do. Her mind reacted to difficulties between you by recategorizing you as the problem and it serves her ego in some way to keep you there and put all the blame on you. She would be crushed, I think, by having to admit otherwise. It is a massive, over-defense of self. But I dunno. Just taking a stab in the dark here.
Perhaps, on the upside, she is having some time to decompress a bit and see firsthand if she wants to parent alone or not. She has time now to adjust to the changes in life with the baby present and perhaps has time to face her fears over her father's health, no? It is taking a painfully long amount of time, but somewhere inside she is having to sort out where you fit into her life. But given all you've written these last weeks don't doubt you are a good guy, and have been giving your all, and that you will be fine with or without her, okay? Her words that you'll never do any better are just words. You will have plenty of chances to meet someone new/nice if that is the way this all breaks and it is crappy of her to insult you and say otherwise. It is simply not true and intentionally mean. It is so hard when our partners take out all of their stuff on us, and worse, that we are often treated worse by them than they treat everyone else in their lives. We get the short end of the stick for sure.
It almost makes me wonder if you can steer out of this blame construct she has set up by modeling a bit of appreciation - either verbally or in writing. You have a lot to be mad about too, and could "blame her" for not taking any blame, but I wonder if one way to keep trying, or flip this, is to just express appreciation for certain things that you like about her and perhaps she'll eventually pick up the thread and gradually remember to say a few things she appreciates about you.
I know this will take a lot of depersonalizing and you might not see results, but at least you will know you speak with kindness, even in the face of cruelty, time and time again. It will become your own practice.

I think it will it also help to get out of the trap of "I'm doing this, she's doing nothing" trap." You just do all you can, no more, no less, no matter what and she is doing what she can do, no more or less, based on what she is able to offer or not. It just is what it is. Depersonalize, over and over, to release the pain. I am picturing you both as two gardens, one that is a bit more healthy with lots of flowers and plants and another that is at an earlier stage of growth with tiny seedlings just above the ground. But they are just two gardens. Nothing to be mad or resentful about.

I dunno. I think it takes lots and lots of re-centering on this stuff, and it is exhausting, but every time you do it it is a gift to your son. Your son needs you to always be doing all you can to help his mom stay balanced to minimize the amount of damage she could potentially do to him over the years with her highly unregulated emotions. Let him be your strength and your guiding principle when you have no idea what the heck you are doing or why.

Take care man, here with ya through this step by step!