I agree with Phelana regarding the short stay. But, if you really meant that you will have 4 days at your destination, then Bonaire remains a possibility. Consider staying at Sand Dollar or Den Laman condos and dive with Bonaire Dive and Adventure on Bari Reef. Sand Dollar has an honest to goodness small, real (i.e., ocean generated, not trucked in) sand beach created by the junction between the Sand Dollar shore front and the BDA dock. Folks who are not diving are commonly found there sunning or swimming. In addition, it is an entry point for snorkeling, either northward along the Sand Dollar frontage, or around the dock (where there are many, many fish to be seen) or a bit further south to the "aquarium" where many other species can be seen around a collapsed dock. Some snorkelers venture further from shore to the edge of the reef where the water is about 25-35 ft deep. You might enjoy a shallow dive while your wife is directly above, snorkeling.