I think part of the problem is that conventional, stable relationships are boring to roleplay about!
I disagree.
However, even in unstable relationships: there are many ways to be unstable. Some make more sense medievally than others.
But it's not really just about relationships. Take religion. It seems like well over half the religious RPs I see are extremely abnormal hyper-ritualized settings; that is, not rituals in which I can see thousands of people participating.
