I know you want to protect your children. That's was good parents do. Since I don't know you or your children, I can only say what I would want my mother to do. Is there someone who does know you and your children who could offer advice? I may not know you but I have faith that you will do what's best for you and your kids. I know it will be hard for them to know you're suffering and not being able to help. But they may still want to know. Something you might consider is putting it in writing how much you love them and the reason for not telling them. Put it with your legal papers so they'll find it. Then someday, hopefully decades from now when the inevitable happens, they won't have wonder why you didn't tell them and lean on them for support. As long as I have breath in me, I'll be praying for Divine guidance for you. You have much too much on your plate to handle alone.