Back to the OP's question, my DH and I have both worn nice shorts/jeans and shirts in the MDR. For Palo dinner or formal night, I will wear fancier dresses; he will wear a button down shirt and nice pants (no tie). I personally would not mind if he wore a tie with his shirt on formal night; I think he looks really nice dressed up.
We both work from home, and I go to the gym right after work 3-4 nights during the week. I wear my gym clothes all day so getting a bit dressed up for dinner when I feel like it is nice. Since we used to fly for all of our
DCL cruises (leaving out of NY has cut down on that part), we also had to be mindful of luggage weight.
When I was plus-sized, my clothes took up a lot more room in my suitcase so I basically stuck with one outfit for the whole day. Now that I am smaller, I can fit more clothes into my checked bag.
There have been times when we've rushed back from excursions with no time to change into nicer clothes. Our tablemates did not judge us for this, nor did we judge them if they chose to stay casually dressed.