We are now in our late 40's. We both decided that we didn't want to have children, so there won't be any grandchildren running around. I think now that that makes it even scarier for me. It kills me to think of having to be alone without him. I can't even imagine it.
I know. I don't have children, either. It is very scary and sad, but you are still with him right now, and are not alone. Focus on that. He has felt shame and guilt already--he should! This is a good thing. Perhaps it's a major wake-up call that needed to be had in order for him to realize he almost caused himself to lose the best thing in his life---you.
By the way, about the weight loss, it's normal. Most of us here dropped down to very frightening sizes. You will need some time to become stable from all of this; stress causes our bodies to go haywire for a while. Just try to eat/sleep and rest when possible. It gets better.
It is unfortunate that you were ever put in this position to begin with. My best to you.
Most of us really marry only once. First love endures, even unto our dying day. And we never really divorce.