My mother once told me, 'You can call yourself anything you want as long as you sign legal documents with your legal name.'
When I married (late 60's) I knew I could keep my unusual maiden name if I wanted but chose not to. I felt proud to take my husband's name. When he died, friends asked if I'd go back to my maiden name but I didn't want to.
My son lives with his partner and her son, who uses Mum's name, rather than that of his birth father.
When I write to them (dgs loves getting mail) I address the letter to the "The *Bennett-Vodanovich Family" so no one is excluded.
My dgs loves this idea and says he wants his surname added to my son's. That's well into the future, if it happens.
*not their real names of course.