I don't know if it is type related. Some people are more open than others. Sx/so are some of the most open people I know but most would not share their passwords with just anyone. A big part of it for me is issues of control. I want to control and protect the context of my private interactions with others. I will probably tell someone anything they asked, about me, but anything I write is personal until I decide the time to share. I try to keep a record of my inner world but it can be disjointed and I would be the only one to decrypt it.
If someone were to look through my journals and messages I am sure there would be a lot of misunderstanding if there was no context. I had to deal with an ex ILI sp/sx with severe jealousy issues and my Fe did not help the situation. I learned to control and keep things from him that were innocent but he would have felt betrayed. It was like walking on eggshells with him for the first part of our relationship.
We were both private people but he took it to the extreme and didn't even want me to privately discuss our issues with my closest friends. I couldn't even talk about his talents (guitar being one) without him telling me not to tell other people his business. How much money he made was off limits even to my mom. I chose him over everyone and I settled into him being the only person I could talk to for a long time. He even downloaded a password crack and looked at everything on my computer at one point.I would never go that far. I would just ask once I had enough info confirm suspicions. What he found was an archive of fantasy and mental masturbation. It got ugly because those were my private thoughts and he had no context. :/
It was self expression. Unfortunately I am jealous too and this relationship (more than any other) set the tone for how I deal in relationships now. I feel that I always have to keep everything private and not expose the other person. Don't show genuine affection in public because it is "wrong". This goes against my natural instinct that says, "fuck what everyone else thinks and show how you feel". In a sense I was trained at a young, and still impressionable age, by a gamma to repress and control myself. Made to feel stupid even for expressing too much Fe.This is a real conflict in me.
But regardless I appreciate everything he taught me and I think I got to experience the world from a totally different perspective than I had previously, where I let my sx instinct run rampant and unchecked.
I realize I am a big hypocrite too because I have spied on my exes but only when the truth was hitting me right in the heart. I knew something was wrong and once I followed my instincts it all came out and yeah I kind of blew up and acted irrational and crazy. Then they could not deal with my emotional fallout and they pulled away until I chilled the fuck out. Probably the best thing for someone to do when I rage but for me it was frustrating. I wanted everything (pour out their heart like I would) and was getting nothing.
I was also taught to keep secrets from a very early age, (4 or 5) even from myself. This gave an impression of someone who had multiple personalities (I am not convinced. In fact I kind of reject that notion now but it made sense once). I am not willing to say that it was due to sp issues but in a way it was a survival instinct working in the background, as it should, imo.
SOME of my sp first friends can be a bit obsessed about maintaining security and privacy, like on the internet or they have alarms on the cars and homes. I imagine if someone is out to do me harm no alarm will prevent it so why even think about it. I am never obsessed with it. I usually don't think about it until after the fact. hahah
I would not give anyone a password to something like my email or forums. I give my netflix and hulu password to several of my family members and would also give it to close friends. I think I am naturally trusting with a healthy dose of skepticism, now. I can also be very naive and trust someone I feel is trustworthy based only on their energy. Sometimes I am right but other times I am so wrong.
/tangent
Edit:
This bothers me, unless it is a friend and we are half joking. When people do this it makes me want to play devil's advocate. I really don't like to gossip and usually it is presented in gossip form. One on one I can deal with it but when people do it publicly it is irritating. I had an issue with this recently and I held my tongue but right now I really wish I had spoke out.