This is a fantastically looking watch.
The moonphase + date with power reserve is a petite combo.
I enjoy this combination very much also, but mine is the discontinued reference 5055 and in another metal.
The "Naughty (opps, that didn't come out right, I mean Nautilus) interpretation of this petite combination is best featured in rose gold. And the leather strap makes it very sexy.
Superb choice. You are a thoughtful wife !. He should set the moonphase and date to fully enjoy the watch. Dec 17 is the next full moon. A good opportunity to set the moonphase. Remind him !
Cheers.