I agree,
We have the his, mine and ours. The ours is the bigger share, but not all is ours.
We know some of the passwords but not all. Only where appropriate. He can get into my computer but will always ask for permission. The reason for this is because he is the iT person around the house.
He does not know my email passwords and I do not know his.
The same goes for bank accounts we do not share pin numbers and we do not share the mobiles.
Yet at the same time we are not secretive about it at all. When we feel somebody has to see something we show it. We share a lot of these things, without giving access if you know what I mean.
We are married, we have not become each others property, accessories or commodities nor have we given up being two people. It is not a question of trust. I trust him, he trusts me. It is a question of identity. IMO divulging all your personal stuff is more about co-dependency creation and control than it is about trust.
Trust and love mean that you don't need to know everything and can give each other space to be who they are without you
With my ex I shared an email account (mine originally) when things got ugly I nearly lost it. Thanks to a very decent understanding customer service person I did not.