||1) Connect to the shared drive and mount it in the Finder.
2) Open system preferences
3) Open the Accounts preference
4) Select your wife's user account
5) Click on the "Login Items" tab in the right pane
6) Click the little "+" icon to add an item, select the shared volume
from the Finder, click the 'Add' button. Instead of clicking the "+"
to add, you could have simply drug the mounted volume from the Finder
into the Login Items window.
7) Exit system preferences and restart.
Now when you re-boot it will ask you to authenticate the volume and it
will mount automatically. You can choose to save the login to the
keychain which I think will by-pass the prompt.