We don't get to say bad things about their dad, but we don't have to defend or protect them, either. I tell my kids that sometimes grown ups don't make smart choices. I even go so far as to discuss with them what a better choice here would have been. How are they going to learn right from wrong otherwise? I tell them their dad loves them. I tell them they are my whole world, and I tell them when things are out of my control and apologize for their pain. It totally stinks!