Carnival still gives a kitchen/galley tour, but I don't think RCL does. Nearly all the ships used to give an engine room tour, but since 9/11 I don't know of a single line that allows access to these areas. It's a shame, because it's an amazing tour!
You'll enjoy the cruise anyway, and if you're lucky, you're husband might be able to corner one of the engineers aboard, and talk to him about the "inner workings" of these great ships. It's fascinating!