I don't see anything wrong or sinful with that. I guess we can call ourselves whatever we want.
I've preached on the wife taking the husband's name and comparing it to the Bride of Christ being called by her Husband's name. I've used
Gen 5:2 where God called "their name (singular) Adam." It's a good thought for preaching and I believe we are called by our Beloved's name but I don't see how that should result in some kind of a civil law requiring married couples to use the husband's last name only. Those things are just traditions and vary from time to time and place to place.