Well I would disagree with your wife. Stating "The Smith Family",when Smith is the head-of-household name, indicates one family. And includes everyone living in that household.
And even a married woman who doesn't take her husbands name can still be referred to as "Mrs. John Smith" because she is Mrs. John Smith. "Mrs Jane Smith" would be incorrect however.
wrong. wrong. wrongo baby! She could be referred to as Susie Salmon Butt but that's not her name either. She IS who she says she is and no one else. If you insist on calling her the wrong name, that's about you and nothing more. BTW, there is no 'head of household' in our family altholugh my husband would laugh and tell you I was. Why do people get so hung up on this name thing. It's the patriarchal religion thing, right? phooey!