In Google Calendar, when I share my primary calendar with my wife by typing in her e-mail address, the only option is “See only free/busy (hide details).”
However, I am able to share other calendars I have created (not my primary calendar) and grant anyone rights to see them or even to edit the calendar.
I considered making a secondary calendar and using it as my primary calendar—leave my real primary calendar blank. However, when you add appointments, it defaults to the primary calendar. I’m sure I would constantly be adding appointments to the wrong calendar.