I feel your rage. You would be well served to take a deep breath. Who was this woman earlier in your relationship? I have referred to my W on these boards as an "alien" for good reason. She isn't the person that she has been. She is acting out in every direction. She is not caring for the house. These are all things that are not normal personality traits for her.
It hurts, but we cannot fix them. Telling them they are in MLC doesn't help. Eventually, you will look inside yourself and inside her to understand how you got here and evaluate who you are going to be. That's the only thing that matters at this point. "Keeping score" of her actions and transgressions may feel good, but serves no purpose.
You have it right, that it is childlike. Think of it that way. She is returning to an earlier place in her life to relive something that is unresolved.
Patience, JF
Both 40 T-22 M-18 S13 S11
Bomb, ILYBINILWY-7/10/13 EA #1-confirmed 7/10/13, ongoing since 5/13 EA #2-9/13/13