You need not be positive about their mom, be authentic, just don't be negative about her as a mom.
It's ok for your children to see you hurt, to know you love them, loved their mom and that her behaviour is not ok.
Otherwise when that time comes, your message is different from the one you have given all along. And authenticity means your children know you are not going to dodge the tough stuff in life and it's ok to be open. No secrets or making things jolly which aren't. In other words the truth as appropriate for their age, without drama or blame is fine. They know when parents aren't being authentic and it creates cognitive dissonance.
Nefler is right it is her loss and you can be sad for her.
Frankly I want to punch her on the nose with a wet flannel.
But that's V
V
Freedom is just another word for nothing left to loose. V 64, WAW
