The book ‘Super Mario Bros. Side-Story’ was released in 1986 and tells the tale of Mario going to Peach’s wedding, which isn’t to him, but the prince of the Potato Kingdom, Prince Andre.
The second book in the series ‘Super Mario Bros. Side-Story 2’ sees the Prince and Princess married.
Or maybe Peach loved Andre at one point, but cheats on him with Mario, her childhood friend?