Based on what you have said there’s not a doubt in my mind that she was trying to set you up based on her girlfriend’s similar actions.
When a spouse decides she wants to bolt because the relationship doesn’t deliver her with her expected lifestyle anymore one of the most prominent things on her mind will be how best to misdirects from what she is about to do and its effect on the kids. And that’s where strategies like this come into play as they don’t just immediately position the mother as a victim who had no other choice, but also they ensure she gets the majority of time with the kids, which means the kids have less chance to think mum did anything wrong.
It’s disgraceful how often this stuff happens and how easily it works. Be careful, don’t get into any arguments at all with her, and don’t follow her instructions to tell the kids off.