Well, to determine if 'Upside' is a true story, you'd need to look at the source and the author's statements. Sometimes, stories can be inspired by real-life but have fictional elements added for entertainment value.
Well, it is indeed inspired by real events. However, when it comes to the movie, certain elements might have been exaggerated or fictionalized to make it more engaging for the audience.
I can recommend the following novels that reverse love:
1. "A Love Story of Reversed Day and Night"
2. "Upside Down Love"
3. Love is Upside Down
These novels all used reversed love as the theme, showing unusual love relationships through the plot. However, due to the limitations of the search results, there might be other similar novels that were not mentioned.
An 'upside down novel' could be a novel that subverts traditional narrative structures. For example, it might tell the story backwards, starting from the end and going towards the beginning. This can create a sense of mystery and make readers re - evaluate the story as they go.