Although you said your DH can't go swimming, think about a snorkeling trip on a tourist boat. He can sit in the shade on the boat, and you can snorkel. It is the MOST amazing thing in the world, and a treasured memory of mine, seeing colorful fish and sea turtles and coral, etc. The operators are most helpful with people who have never snorkeled before. In fact, my husband is a non-swimmer, and they gave him a buoyant life vest and a viewing box so he didn't even have to put his face in the water. On the boat they serve drinks and snacks, and the views are lovely, so your husband won't be bored. I took a waterproof camera to try to capture the beauty, but my pics were never as good as professional pictures and postcards. Don't miss this opportunity to do something so amazing!