I never thought I'd be cynical either, but I am too. I wished and wished and wished for any sign of recovery. When the promise to quit came, I was done waiting. I am happy for my own husband and wish him recovery for himself, whether we stay together or not. I think your feelings of fear are normal and okay.
I think Thumper has the perfect advice... put together a plan to get you to a point where you can take care of yourself and your kids regardless what he does. He may be sincere and recover, he may not. Only he can control that. By taking care of yourself, you'll feel better.