You might check the "Caribbean" board under "Destinations" for information on the various ports of call. Unfortunately, she is swapping itineraries with MV Dawn Princess for this winter season so I probably have not been to any of her ports of call except St. Thomas. In St. Thomas, though, I highly recommend the Champagne Catamaran Sailaway to St. John. I took that excursion last March, and I'm looking forward to taking it again when I return to St. Thomas aboard MV Sun Princess in September. It definitely is worth the $96 fee (which, BTW, is less expensive than the fee if $118 for golf at Mahogany Run, so your husband will have no basis to complain!).
BTW, do wear your bathing suit under your street clothes on this one. You will have plenty of time for either swimming or snorkeling when the catamaran anchors off St. John. The crew of the catamaran will provide a complementary snorkel lesson and equipment for your use.
MV Ocean Princess is a magnificent ship. Do enjoy!