Infidelity & how to verify orders

Im a SAHM of two toddlers who has been forbid to work basically. I tried but he didn’t respect my hours and picked up over time without any concern to my schedule. So im broke . He is in the military part time… gone 1-2x a month on orders. While organizing I found a cruise room key with the room number, his name and everything on it. Per him he booked the cruise for someone else so they could use his military discount and they paid him the difference so he made like 300$ from it . he says he was never there . I confronted him after I called the cruise line and they said there is NO WAY a room key would be issued without valid ID. so unless he committed fraud he was on that cruise . hes gaslighting me saying that im trying to find a problem and he was on orders . I asked to see the orders and it’s been days . would his higher up falsify orders for him ? is there anyway a room key could be issued without the person stepping on the ship ? im so lost .

Edit: it was over a year ago dated for the EXACT days he left on “orders” I was heavily pregnant at home with a toddler and no car .