Bube, You know what strikes me about this last post? Most of it is about how W is with other people. There is very little (none?) about how she is with you. Is she generous to a fault with YOU? Etc etc.
I can't envision a marriage in which I get nothing out of the deal. Further, I can't imagine a family life where my kids steer clear of my spouse and their anger.
I know you have a shared history with her and I really do understand the strong pull that creates. I am not suggesting that you abandon her; I'm simply suggesting that you carve out a life for yourself that does not include her, since she has essentially refused to be a wife to you.
I know it will cause a bunch of strife and trauma in the immediate future but I would think that eventually, when the dust settles, you will find that you are a happier person when you are not having to constantly provide her supply, as well as run interference between her and the girls.
In other words, you are obligated to live out your vows, fine, but you don't have to keep trying to squeeze the lemonade out of your lemon. She's not going to produce.
Detach yourself from her, slowly, I know it will be hard for you, and see if it brings any semblance of relief or balance or contentment in your life. It appears that you've been trying all these years just to get her to contribute to the R and she has failed. She may not have it in her.
Perhaps this is your lot in life...to be married to her...but it doesn't have to be as miserable as it is, kwim?
And I doubt you are the only one to have noticed her NPD traits. Most likely anyone who's come into regular contact with her will have an inkling of what she's like. I suspect that there is a trail of left behind friends and acquaintances who caught on to what she's all about and she cruised thru them like nobody's business. Please don't let that be a hindrance to making a life for yourself..they will most likely figure it out soon enough.