Trust goes both ways, and while haveing privacy is fine, if someone shut of their computer every time I walked into the room I would feel like perhaps that person did not trust me either ( that maybe I am the issue) not even that they might be hiding something although if it was constant sure one might feel that way. Like sandman said just talk about why you do it. We all like our privacy sometimes.

I would say that if it is ALL the time, perhaps it isn't bad to try to not do it all the time. And you can judge what you might be willing to share. Relationships are about shareing your life with someone. If someone was needing privacy all the time for things like browsing perhaps there is another reason why they do not want to open up at all. Not saying that is the case with you, but it could seem overly gaurded.