I am really sorry you're going through this. Much of what you've described is happening in my own relationship, too. So I really understand how hard this is. I also feel really really confused most of the time. I have no idea what to do, either.
What I've found is that your wife is everything you see. She's the wonderful person you remember. She's the mean and cruel person, too. And it changes from day to day, minute to minute, but all of those things are inside of her. The reason I say this, and the reason it's important, is that you might get those great days again, but you can just as easily and just as quickly get the bad days.
I've also found myself in deep financial trouble because instead of following a responsible financial agenda, I left it up to her strategies of avoiding the hard decisions and ignoring the consequences. I knew better, but I followed her lead anyway, and that's what happens when we twist our lives against our better judgement.
I also have a 4 year old daughter who gets the "attentive" mom some days and the "I can't be bothered" mom other days. I've watched my daughter break down in tears because Mom couldn't follow the bedtime rituals - whatever argument we were in the middle of was more important, and if she couldn't finish the argument with me, she wasn't going to do anything for anyone.
Having said all of that, my life has improved quite a bit since I started looking at things from the perspective of, "what can I do to move things forward for myself?" - because in the end, we can change a lot of things about ourself if we know who we are and what we want, but we can't change anyone else, no matter how hard we try.
Have you taken a look at the perspective articles on the right hand side of this page? Several of them are at the link
What does it take to make it. If you have a minute, take a look at a few of those and see what you think.