I wish one of our employers would offer one of us a free cruise!
I am in the "Suck it Up" camp. He knew that he'd have to do this when he accepted the job. Honestly, in today's employment market, who turns down a job because they don't want to go on a week-long cruise? If he doesn't go, he won't have to worry about next year's business trip, because he is going to be viewed as not a team player, someone not dedicated to his job, and he'll be working for someone else (or unemployed) before the next business trip rolls around! Time for both of you to grow up!
Besides, a week is not that long. DD22 and her very serious BF23 had just started moving to Connecticut and setting up their apartment when DD had the opportunity to take four 11 year olds to Portugal, to participate in an international gathering to promote international peace and understanding. Of course she went- fabulous opportunity for her! Her BF stayed home, set up the apartment, worked his job, etc., and they were SO happy to see each other when she came back! Certainly if a couple of "kids" just starting out on their exciting new life together can manage a month apart, you can manage a week.