Over the years the dress code has changed & I can't find where they "suggest" that you remain dressed throughout the evening. It was that way a few years ago but somewhere along the line they seemed to have dropped it. Since the inception of dining at the Horizon buffet for dinner with no dress code other than shirt & shoes
it would be inconsistent to require people to dress for the shows.
In any event the majority of people do dress for the "formal" dinner but some like myself & my wife do a quick change immediately afterwords to more relaxed clothing & have never been questioned in any lounge or showroom. If you can get you husband to put on a suit jacket & pants for dinner (without a tie) he'll be fine. On casual nights he can ware his jeans (no rips or holes) with a simple 3 button **** & fit right in with the crowd.