My guess is that your kidlets wanted some way to voice their complete and utter disdain of the new GF, so they did it through a "well mom said."

You could just sit them down and let them talk about how they feel about the new GF and having her introduced into their lives. My guess is they are less than pleased.

She has no real desire to work out an issue, if she did she would not have gone for the big drama confrontation. Instead, it sounds like she wanted a big show down she could relate back to her friends over drinks.

I find in dealing with people like that less words the better. The more you say to her, the more she has to respond too and the more attention she gets.

I would simply say, I am not speaking with you and close the door. It is neither your job or responsibility to make her feel better.

The bottom line is you are not this women's friend or family. You do not owe her an explanation of you or your children's actions.