One of my best rated stories, I cut the demands short with a denouement that said as a cold hard fact that the two people never saw each other again. I wasn't thinking of it that way at the time, but I'm glad I did it. It was a really romantic story with a relationship that could have easily gone on, except it was built into the premise of the story that it couldn't. (And the never seeing each other thing was obliquely pulled from personal experience)My experience with writing a follow up story to one I intended to be a standalone story was that the results were disappointing.
I got several comments saying that readers wished it was otherwise, but no demands for a sequel.