Do you know any stories (books, films, TV) where people have to stay away from each other to save each other?
I think there was a (science fiction?) movie with this message. For some reason, all humans would have to isolate themselves for a short time to save the planet but can't really remember any details.
What comes close is the "His Dark Materials" trilogy of novels whereat the end you have the two lovers Lyra and Will who have to decide to never meet again and close all barriers between their two universes to save all existence.