I think these sorts of things are exactly why I think it would do the game well for marriage to be revisited (not in the base game of course, but maybe in an expanded marriage mod). I agree with the sentiment that marriage
does come with compromises (whoever you marry is obviously gonna spend more time on the farm) and it's nice to see when characters get out! For me at least, a lot of the parts that make me sad/that I'd wanna fix if I modded SDV are in the details. For example, when you marry Shane the state of his room doesn't reflect his development at all and I think that kind of sucks mainly because it doesn't feel intentional. I
do agree with him having optimistic/pessimistic dialogue on different days though, you can't expect recovery to be easy. I'm really only mentioning this because I like keeping track of the game's inconsistencies in case I get the time/will to learn to mod but haha tangent oops. What I
will say though is that I kinda wish he'd do a little more post-marriage, either talking more about making his passion for animals into a career or at least working at the movie theatre. Making new animations for each spouse's activities would probably help a lot more than expected, even new dialogue to show that they did something in the day! My heart can't handle just seeing Sam talk about how he misses Sebastian.
Maybe it'd be cool if once or twice every season your spouse tells you about an event they're really excited for at [X] location, and if you go there and talk to them it triggers a cutscene where you could be part of it? Maybe then that'd provide some new dialogue options and let them seem a little more autonomous at least!
Plus if they want they can guilt you for not going. I guess this has just been a lot of rambling but hey I have a lot of ideas!