Would they ask that? Because chances are that for them, their family feels perfectly normal. And since single parents are common now, childs would just asume that there are different families.

By the way, at that level, chances are that they go to school with children from gay parents, famous people who travel all the times, that they have nannies and that the extrange thing is that not everyone has a nanny...

They don't need to lie, thay can just explain that their family consist on 2 parents that aren't together. Then, they can tell the child that they love them and that they have people who loves them. And that's it. Here, simple.

It is the people like you who would told those children that there is something wrong and try to make them suffer to punish their parents for not doing what you would want them to do. So don't pretend to care for the children because you obviously don't.