Este.
I believe that relationships involve compromise and marriages requires sacrifices. The latter is especially true once kids come along.
Your wife told you there is something she wants to do and would like to experience. You have no experience with it, but assume you will hate it so refuse...repeatedly. My position is if you love your wife and family (or want to try to) then you can be honest and say it is not something you would want to do, but if to her (or the kids) it is something important then you make it important to you. You go, have as good of a time as possible, don't intentionally act miserable or cunty, but try to be happy and supportive as much as you can for your wife and kids. Cruises have both good and bad, but if you try to enjoy it and the time with your family you will have some good times and some good memories for all of you. They may be packed in between memories of a bunch of fat, oiled up, gluttons, but they will be there.
Be the man/husband/father you want to be for your wife and kids. How you dress, interact, engage, support and speak with them is who you are...intentionally to them. You can control this.
Right now if you honestly described yourself to your wife based on my criteria above would you be happy with who you are. With who you are to her and to your kids (they see how you two interact). Again, you can control this.
Not trying to shit on you, but about 3 years ago I kind of went through this and decided that part of making my life/marriage better was having my wife see me (through my actions) as the man I wanted her to see. She has a similar role to play, and I can talk with her about how I want her to be to/for me, but I only control me.