I've been there with family. And it takes a toll. It's very consuming. When you are someone who is a giver, you end up giving away yourself. It is NOT selfish to focus on you. Just remember that. Life should be 51% focus to you and 49% focus to everything else. You can't help someone if you are defeated. And children will build up further resentment toward the other one if they see you are suffering too much. Just make sure to allow yourself happiness.