Yes, the emotional trauma that they have to face as a result of that. But at times it depends, some of the cases, the children wants their parents to divorce. (Because one is abusing the other or some undesirable situation). From a bigger stress to a lesser stress. But still, it is a problem.
That’s the problem there, sometimes these parents I notice these days, tend to scold their children more for the minor things or too much at times. These add up, and as a result of fear of getting further scoldings, the children will tend to keep things to themselves. So understanding kids/children go a long way.
Yes, they open up to siblings more first, before the decision to bring up the matter to parents. That’s usually the case. The question of whom you can trust.
Some of us we face the negative things in life as a child and we grow up, we remember as much as possible for the same not to be done to our children.