Crocodiles here are part of the amazing flaura and fauna that we have on the caye. They are fascinating to watch if you are lucky enough to see one. You are unlikely to see one unless you go looking and as Elbert said, the best place for that is in the back lagoon areas. They are primarily fish eaters and there are plenty of fish for them to eat without bothering with large and aggressive humans. Remember that as far as most crocodiles are concerned, humans are the threat, not the other way round.
Just remember that feeding them or bothering them in anyway is illegal.
The water here is so clear, warm and wonderful, any concerns your wife may have will soon melt away.