Hi Jim,
BIG WELCOME to Cruise Crazies glad you've jumped right in..
Good topic this one & everyone has their own oppinion (quite rightly so otherwise we may as well all be sheep!)
My personal opinion is that on casual nights jeans are not a problem at all but I think I would feel out of place on a formal night as the whole ambiance of the night comes across as everyone making a big effort & helps towards the whole cruise experience - but then again if someone wanted to wear jeans then there is always alternative dining options to consider as well.. I dont think someone would "get away" with jeans on formal night on, say, one of Cunards ships but then we all know Carnival, NCL, RCCL etc etc are just a bit more casual and thats one of the reasons why we book them.
p.s. nice picture of you both..
Karen