Children are not more resilient than adults. Many adults are damaged by things that have happened to them in childhood.
My ex has had such a terrible influence on our children’s lives (too much to get into but I’ll summarise by saying he has no interest in them and zero interest in being a parent) and when he lets them down time and time again, well meaning people say this to try and make me feel better.
But it’s nonsense and it doesn’t make me feel better. He’s causing emotional damage that they probably won’t really understand, recognise or heal from until they’re adults.
Now that they’re young teenagers, I can see they’re gradually realising what a waste of effort he is, and I don’t think it’ll be long before they decide to have nothing more to do with him. I can’t bloody wait.