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You could change the permissions on the files that need to be private by right-clicking on the file(s) and adjusting the read/write access accordingly. Add your user account and your husband's user account and allow access only to them and Administrators. Since all accounts meant for daily use should be Standard ones, no one but you, your husband, and your emergency Administrative account will have access.

General Recommendations For Setting Up User Accounts in Vista:

You absolutely do not want to have only one user account. Like XP and all other modern operating systems, Vista is a multi-user operating system with built-in system accounts such as Administrator, Default, All Users, and Guest. These accounts should be left alone as they are part of the operating system structure.

You particularly don't want only one user account with administrative privileges on Vista because the built-in Administrator account (normally only used in emergencies) is disabled by default. If you're running as Administrator for your daily work and that account gets corrupted, things will be Difficult. It isn't impossible to activate the built-in Administrator to rescue things, but it will require third-party tools and working outside the operating system.

The user account that is for your daily work should be a Standard user, with the extra administrative user (call it something like "CompAdmin" or "Tech" or the like) only there for elevation purposes. After you create "CompAdmin", log into it and change your regular user account to Standard. Then log back into your regular account.