I think if they last name matches you should be fine; that's the criteria they use when transferring chars between accounts, as long as the last name matches. Moreso if you're in the same house, if they get suspicious tell 'em what's technically the truth; it's your wife's account and you play in the same househould and therefore on the same connection, so of course the IPs'll be the same and possibly be on at the same time :p