Think about those kids telling you how much they love you.
Think about all their first milestones, steps, words, etc.
Think about their birthday parties.
Think about them dressing up for Halloween.
Think about them hugging you.
Think about teaching them to ride a bike.
Think about taking them for ice cream.
Think about tickling them and making them laugh.
Think about the pictures they'll draw for you in school.
Think about going on dates with them.
Think about taking them to the zoo.
Think about taking them to the beach for the first time.
Thinking about telling them bed time stories.
Think about drying their tears when they're sad (or have hurt themselves).
Think about comforting them when they're scared (like a loud thunderstorm)
Think about encouraging them when they're down.
Think about teaching them to read, and once they learn how, laying beside them as they read "Cat in the hat" to you.
Think about taking them to see Santa.
Think about taking them to the park and pushing them on the swing.
Think about taking them to the movies and buying them popcorn.
Think about them dying Easter eggs.
Think about them coming home and telling you a good grade they made on a test.
Think about their graduations.
Think about their weddings.
I can go on and on but I think you get the picture.
Listen, nobody knows how long they have in this thing called life. Your life is like a novel. There's going to be great chapters where you can't turn the pages quick enough to find out what happens next, and there's going to be chapters that suck and you'd just soon forget what happened. Good things are going to happen and there WILL BE BAD THINGS AS WELL.
That said, just like a novel, each chapter (good or bad) will come to an end and a new one begins.
Sure you're experiencing something that tore you apart previously and you don't want to go through it again.
As others have said, you got through it before and YOU WILL GET THROUGH IT AGAIN.
This time however you have those two little ones to inspire you.
Hang in there and PLEASE confide with someone who has experience dealing with these emotions.
God bless you my friend and praying that you find the peace you're seeking.