I am sure no one thought they were a sitting duck when the headed to work at the WTC on Sept 11, 2001.
But if it makes your husband feel better, security at the port is very tight, everyone needs documentation just to get IN the terminal, and all baggage is screened. Also, I believe there is a radius around large liners where no other watercraft should be in; similar to a no-fly zone. When the ship is docked in Nassau, only guests on the ships are allowed anywhere near them.
But like most said, it's a personal choice. Terrorists want us to be afraid, but also, if you don't think you can enjoy the trip, because of fear, then it won't really be a vacation, so why invest all the money. Terrorism will always be in the back of our mind, it just depends how we let it effect our decisions and choices.
It's a scary scary world, thank goodness we have places like Walt Disney World, and
DCL to give us a little bit of happiness, and that child-like innocence back, even if it is for a week or so.