It's easy to give someone your FB password, your email password, access to your phone, your Internet login.

The only thing easier is to have other FB accounts, email addresses, even phones...Ones that your other half know nothing about.

Trust is not built through constant surveillance or monitoring. If anything it breeds mistrust.
I completely agree. DH has betrayed my trust with an online emotional relationship and a real life one (not that he sees it). Even with that, I would not demand his passwords etc, Whilst a part of me would want to control that much, the major part of me actually feels sick at the concept. They are grown men, not little children to be monitored and if I felt the need to monitor every move, then for me the damage as gone to far.