I view privacy as a basic need that people have to differing degrees. I am a private person, and get irked if somebody uses my computer, phone or what not. But that has more to do with my past than with anything else.
I see privacy as a way to control how much of our inner thoughts and experiences are available and accessible to others. People in institutions come up with myriad ways to keep even the illusion of some privacy intact, which is why I think it has to be a basic need of some sort.
As to privacy in relationships? Some people are fine peeing with the bathroom door open, whereas others get uncomfortable even if somebody else does it, and would never do so themselves. Some people are obviously fine with their spice reading their e-mail/texts. I wouldn't be. I am curious as to why someone would feel the need to. Does it always come from past issues with trust and betrayal? You who do go through your spice's correspondance, why bother?
Me: bi female in my twenties