Any fiction books that feature incestuous relationships?
I only watched the movie because I'm illiterate, but Gone with the Wind. But my understanding is that the incestuous couple were miserable because Scarlett was constantly wanting Ashley's dick.
Breece D'J Pancake's story 'trilobites' is about a guy who wants to fuck his cousin. It's not really a major point or anything, like he mentions lusting after this girl a bunch and then it's just mentioned in passing that they're related like it's no biggie.