Me too! My husband, on the other hand, always gains weight on a cruise.
My time on a cruise is spent going here, going there, doing this and that, and OH MY GOSH, look at all that cut up fruit that looks so tasty, and all that salad and fixings, and oh wow, fish, yummy fish, that isn't stinking up my kitchen! This is what my brain says on a cruise, and I love that someone else is preparing all these things for me. I am pretty sure I eat a year's worth of fruit, vegetables and seafood on a 7 day cruise.
My husband, however, is mesmerized by all the meat and the bed. Eat meat, take a nap. Repeat constantly. Let the wife go here and there, while the husband takes a nap. Cruises are eating and sleeping fests for him.
At home, I have a lot more time where I sit, be it in front of the computer, working, or just on the phone. I hardly ever sit while on a cruise, as there is too much I feel compelled to experience.
I believe that I need to be on a cruise for a few months as a weight-loss program. This would work for me.