Very true...it IS non-refundable if you have to cancel close to the trip.
To the OP - my suggestion is for future vacations like this where non-refundable monies are involved, get yourself
trip insurance that covers job conflicts.
My husband also has a job with strict deadlines and we must do our best to plan vacations around those deadlines. Its often not possible to know 12-18 months out if a vacation is going to happen yet the best prices on cruises are often found that early. Our solution? Investing in trip insurance that covers cancellation due to job requirements. Our policies have cost between $75-100 and are never refundable if we cancel ahead of time, but in my mind spending that money at time of deposit is peace of mind if four weeks out my DH says "I can't go".
It doesn't solve the 'togetherness' issue but it will solve the $$ issue.