Please let me reply to this since it appears no one here has actually worked on a ship except me :-)
Don't believe the stuff about long hours and cramped conditions and low pay. IT and Hotel Management staff generally get good pay, work reasonable hours and get their own cabins.
The trick for you is in guaranteeing that you will both be on the same ship. Cruise lines don't need to be pressured into package deals because they already have plenty of applicants.
*IF* both of you are extremely qualified in your fields and
*IF* the cruise lines have an immediate need for your positions
-- you might be able to swing this, but most couples have to prove themselves individually before they get the privilege of living together.
I knew a musical director on HAL that actually bargained to have his wife AND 6 y.o. kid on board full-time, and she didnt even work. But he had been with the company for years and had become indispensible.
If you can do this, apply individually first, get individual track records on ships, accrue references and THEN approach a line about working together.