You don't have to fully let go. And if you feel obligated, then you should do what you can for the kids. Otherwise, I think you'll always wonder what would have happened if you at least tried. But you need to take time when you can and separate yourself. Find ways to make yourself stronger. Find your own activities and friends that make you happy. But I wouldn't let go if you are someone those kids need or can turn to in a time of need.