Yes! And Arthur (and everyone else, too, for that matter) needs to be reminded of this from time to time.

This fic really had everything I like about those two.
And the kind of ot4? Delicious. Arthur being utterly helpless and Merlin turning all red, while Morgana is totally above this. We don't see how Gwen reacts, but in my head she would play along, because it's always funny to see Arthur embarrassed.