I think no matter how much you may even want the divorce, it still hurts. It's a kind of death: of dreams, of future plans, of the vision you had of your life in your head. Once it's final, you move on, but it still makes you sad.
When I divorced XH 1, I remember leaving the courthouse, and watching him walk away across the parking lot. He was an alcoholic, emotionally abusive, and we'd been separated for over a year but he was still my sons father..and it hurt.
I'm sorry you're hurting.