Movie ends halfway truncating the story

This movie, more than others, shows us a story that will obviously continue, with clear consequences to what was presented to us.
Instead of most narratives ever made (like Cinderella, for instance, they live "happily ever after": we know what that means as the events of how she escapes the life of misery to find love and happiness are shown to us, the rest is not important to this story), this movie ends when the events are halfway, not fully developed.

How could it possibly end there?
There is obviously a second part to this story, where Harry is forced to live as a "husband" by Dolly and is cheating on her with Gloria. He's obviously gonna figure out a way to get rid of his "wife", while Gloria might have an agenda of her own, maybe with another woman.
This second part seems more interesting than the first half, which ends in a place where there it cannot.