I was pretty impressed with the amount of dialogue changes that happened when I got married in the game. There is a fair amount of effort to make the marriage feel a bit more special. Every event has new dialogue. The spouse has different things to say depending on where she is. When Abigail goes to her parents, she says she's visiting them. When it's late, she says she's tired.
There is always more you can add, and I think more should be added, especially with the children, but this is probably the best marriage simulator I've ever played. I didn't expect it to be as satisfying as it ended up being. I'd imagine that all the marriage candidates also have special dialogue, and I am pretty sure they say different things if you let their hearts drop too much as well. If what you are looking for is more conversation text, I would suggest marrying all 16 candidates (plus Krobus) for a year. I like that Ape focused on marriage dialogue, rather than other NPCs. If you haven't married yet, I'd strongly suggest you try it.
Also there is a fair amount of new dialogue at the beach.