good question because the “a” could be “to” or it could be “personal a”. and how do we know vuelve refers to the man politely or to the wife. but if you just add the “a” before su esposa, it should mean that. volver used transitively means “to turn” not “to return”: volver la cabeza
Mr Spock says that you are not being logical. So you are saying that when you correctly typed "Sirs" for "Señores" it was marked wrong? Don't see how. And then, in case Duo didn't accept "Sir" for "Señor" you typed "Mister". No, two wrongs don't make a right. Just keep using the standard titles, and report it if not accepted. Simples!