I'm not sure specifically which 'down by love real story' you are referring to. There could be many stories with this name or something similar. It might be about a relationship that faced difficulties or ended in a sad way.
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.
In a way, it is. The plot of Broken Down Palace may draw inspiration from real-life situations and experiences, although it's not a direct account of one specific true story. The filmmakers likely combined various elements to create a compelling narrative.