You are probably best served by setting up a standard user and then using the built-in Windows Parental controls to limit their access, ( I know it's a touch ironic

).
As for your personal data on non system drives you may need to edit the file permissions for those areas - remove access for the everyone group, (make sure you explicitly add full access to you and your wife's specific user name first, if not already there), and any entries such as authenticated users, Homegroup etc., (make sure that the administrators group has full access for a safety net