Once upon a time, in a galaxy far away, but not THAT far, actually:
"my partner and i can't be in the same building without fighting, we never have sex, and want mutually incompatible things in our futures. Also, we don't want to break up because it will upset our great grandparents and our soon-to-be third-cousin, and we'll have to explain it to the mail carrier and hairdresser and fill out more paperwork. So, we decided to try the polyamory-lifestyle."
Three months later:
"why is polyamory not working? This lifestyle is supposed to be DIFFERENT from monogamy, but it has the same problems, only WORSE. My wife is getting lots of action on OK Cupid but it's all guys who are cheating on their wives or only want NSA one night stands. And all i get is replies from girls who just finished college and want to have my babies, or from couples who want me to have sex with the wife while the husband watches. I found a forum and thought it would be a good place to learn from other people's experience, but all i see is one story after another about all the problems people have and how miserable they are. Why even bother doing this if you're just going to end up failing anyway? I haven't heard of a single polyamorous relationship that has lasted forever."
And they lived happily ever after.