rd, I wish I had some advice for you, but I don't know what to say. I guess your kids' relationships with their mother is between them and her, and if she is going to sabotage it or abandon them, there is little you can do except be there for them to help pick up the pieces.
It sounds like your wife is using her for her own emotional support. Can you maybe get her to lean on you less? Draw a boundary so that you can keep some of her crazy out of your life?
I am really sorry that she is damaging her relationship with her kids in that way.
My H also sees no problem in having his GF stay overnight with when our daughter is at his place -- he has no consideration for her feelings at all. It is sad. They are really selfish and self-focused at this moment, and they also want to play the victim so they won't feel so guilty about their actions.


M: 43 H: 39
D: 14
Married 15 Together 16
BD: 6/2014
S: 8/2014
OW revealed 10/2014
Instigated dissolution 12/2014, in progress
So over it!