Thanks Kevrumbo and Altamira. Not sure why kevrumbo's suggestions, which I've seen before in other threads, aren't getting more likes.
Prior to becoming a diver, I had spent time on both small powerboats and sailboats. No issue. However, if I am in a movie theater watching a film meant to simulate motion or playing a first-person shooter video game (which I almost never do because I'm awful at them),
I will turn green (nausea and headache).
My first 3-D movie experience, Avatar, made me sick as a dog.
I can drive, ride roller coasters, and be on small boats without issue (though I haven't yet been tested on a small boat with serious swells.) That said, on my one and only liveaboard, I did have intermittent slight to moderate queasiness and looked forward to being "done" and back on land. I wish that weren't the case but it's true.
My husband dive buddy and I will be doing another liveaboard this December (Cayman Aggressor). So, the unpleasantness is not enough to ruin the joy of diving. However, anything positive I might be able to do to help improve the experience would be great. So, thanks to all of you that have contributed tips in this and past threads on the subject.
Good luck Ofra!