Clueless, when you write about your fears, I hear how worried you are not just that they'll leave you, but that you aren't being as strong as your wife wants you to be. But you are being strong. You are trying very, very hard.
People make the decisions they make because that is what they think they need or want.
We want happiness for the people we love, and we want their love. It sounds to me like she and the boys love you, and it's clear that you love them. Don't minimize the positive, okay?