.....other than I have no idea how you are feeling (and can't unless I walk in your shoes).
But, your wife is in your children and granddaughter. And I'm not talking about blood/biology. It's the family you both built together and they would not be who they are without you both. When you look at them, you should see her. When you think about them, you should think about her.
That's how I think about my wife and daughter.