I don't think theft is the primary concern.

Mine is that the two of you both manipulated and used each other to get what you wanted. She wanted drugs or alcohol. You enjoyed a chance to rummage through people's things.

I was an inmate here. I know how easy it is to get your hands on contraband in port. How simple it is to talk certain wardens into letting you off the ship unsupervised, or even giving you spending money. You had plenty of options besides breaking into cabins.