good question and I commend you for trying to be thoughtful of your table mates. One of the neat things about dining on a cruise ship is to try "different" things (you never know what you might like), so if you're not really into appetizers and salads, you might ask your waiter if you can share with your spouse each of the courses (they can cut the portion for you prior to serving) and if you don't like it you don't have to eat it, but you would not appear to be disrespectful to your other tablemates (or wasting to much food)
You do not indicate which line/ship you are on, but most cruise lines are leaning towards "personal choice" dining which gives you more options on when, what and with whom you dine with
If this is your first cruise, the dining experience is a key part of your cruise. Enjoy the sharing of experiences with your table mates and most important, enjoy the luxury of leisure time and company without the pressures of every day life.
In Europe, they don't rush eating, they savor it