Believe it or not, encountering real sharks may be helpful. Sometimes it's needful to replace a distorted, dysfunctional fantasy with a much more benign reality. The Keys are a good place to do this. First off, nurse sharks remind me more of catfish than sharks; they're about as non-threatening as your going to get. Second, the reef sharks are apt to be something of a let down from a fear perspective (assuming we're talking about no spearing, not hunting lionfish, not a shark feed dive, just a random 'fly by' encounter on a reef dive).
I didn't start out particularly afraid of sharks in general, but I had some working my way up to before doing the shark feed diving I had in mind. Started with Key Largo (
trip report - you can get some idea what that was like), later a live-aboard out of Belize (shark feed dive with reef sharks, some 'passer by' reef sharks), then diving amongst the sand tiger sharks out of North Carolina (
trip report - they look scary at 1st; then you realize it's like standing in a cow pasture. Yes, you're surrounded by big animals that could in theory injure you if provoked, but so what? I grew up around farms...), then later some other species.
If all else fails, the mainstream west coast Bonaire diving is highly unlikely to involve a shark encounter of any kind (8 weeks there over the years, haven't seen one there yet). Aside from the extra charge shark feed dive at a particularly site, I've read Roatan isn't big on shark encounters; anyone know differently? My point is, there are places you can go where seeing a shark is quite rare (Bonaire's west coast), and places it's almost a given (Turks & Caicos from what I'm told).
Richard.