While Mrs. Atrios obviously shares a pseudonym with me, she didn't share a last name. We didn't think much about this when we got married - there were a few purely practical reasons it was easier for her to keep her name - but it seems perfectly normal. Normal, at least, until we realize that for a lot of people it's a freaking weird thing to do.
Mrs. F and I have different last names too. Back in 1990, when we got married, we got the 20 questions routine all the time. For the record, the Mrs. was well-known in business circles before she met me and it would have been a hassle for everyone concerned to make the change. I personally didn't care one way or the other; she's my wife, I know it, she knows it, and that's all that counts. I think it's more fitting anyway (she's an independent woman in her own right and doesn't need to reflect my 'light'* to shine) and I really don't see the logic of changing a woman's name beside the fact it signifies 'ownership' of the woman by the man. I don't see many men taking their woman's last name, do you?
I figured that by now (close to 20 years later) different last names for spouses was common enough where it didn't raise an eyebrow anymore. Guess not.