Happy ending are only a pause. There are three kinds of big endings: Revenge. Tragedy. Forgiveness. Revenge and Tragedy often happen together. Forgiveness redeems the past. Forgiveness unblocks the future.
There are only three possible endings -aren't there? - to any story: revenge, tragedy or forgiveness. That's it. All stories end like that.
Stories end in reverie, tragedy, or forgiveness.