This seems to happen to us a lot. DH is Jewish and I am Asian, and we have different last names. Yesterday we closed on our refi (yeah!) and after about an hour, during which the lady could clearly see our hands with rings on the table, she asked, are you married? I knew he was thinking, not again! We're pretty sure we wouldn't get asked this if we were the same race. It isn't just the last names because people ask us this not knowing our names. They even assume we can't possibly know each other if we're standing right next to each other.
(The insanity did not end there. She didn't understand the concept of not changing my name, and that I didn't have a separate maiden name. She insisted I had to write a statement about my maiden name...DH told me he wondered if she thought he was standing in for my real, Asian, husband.)
Okay, just had to get that out!