Interesting post...very introspective and thought provoking.
I agree that somewhere along the line that you've allowed yourself to be drawn into her drama and maybe lost a little of your self-focus. Atlas, your wife isn't there. She isn't even close to the point where she can be the woman that you need, well that anyone would need, someone that doesn't just take. You are her rock, but she's more like your quicksand. I agree that you need to take a step back.
Want to try a little "act as if"? This time, instead of acting as if everything is hunky dorry, you act as if she is still completely the alien and has never made any mention of reconciling or marriage counseling. Honestly, she really hasn't. She's said a few words, went through a few motions, but she really isn't even close to being out of the fog, if that's what this is, to know what she wants, or pursue it if she did know. Does she want you? Who knows. I'd "act as if" she doesn't know and just step back from her. Refocus on making sure you're happy with the life you can create for yourself and your child and let her do her own thing. If/When she reaches the point where she actually knows she wants you, and isn't reacting out of fear of the unknown, or whatever that's driving her, she can hopefully do what it takes to convince you that she's worth your time. Until then, I'd continue to be there, when you can (although you can't just be her place to land to sober up and the guy that hears all of her woes), while taking the time for yourself as well. She can't come to you with all her problems if you are out living.
In the end, it's not the years in your life that count. It's the life in your years. Abraham Lincoln
It is hard to fail, but it is worse never to have tried to succeed. Theodore Roosevelt