If you believe people in a relationship have a right to some privacy, how does that play out exactly?

Fluther has had some Q’s in the past asking what the collective thinks about SO’s going through emails, or having to always tell your SO where you are at all times. I recently had a conversation with someone about topic, well not exactly a conversation, it was like she was angry at me, and basically she accused me of judging her because I think everything should be open and honest between SO’s, and she feels not everything has to be. I have never said anything directly to her on the topic? I did not even know she felt privacy was such a big issue? Going as far to say that if an SO asks something that crosses the lines of privacy, it is ok to lie. First, I do not judge her. I think each couple makes their own rules for their relationship. But, it made me wonder, the people who don’t feel like they want to share everything nor be open books to each other, do you consider the relationships you have had to be good ones? Were you happy? Consider them successful? Have they lasted a long time. Did you really trust your SO?

I know the wording of this question probably sounds like I am judging people who get angry if their husband looks at their emails, but I am not. I sincerely am just wondering how those relationships go? You both just know or have discussed what will be off limits? I don’t have anything off limits with my husband, so I am just curious.