Steamdeck
One week after marriage, the shown dialogue heart level began "jumping around". Its usually the color below the fifth heart (grey), sometimes it shows up as the 0 heart color (just empty).
I think its determined on a Day by Day basis, as I havent noticed a difference in the hearts when doing the morning/evening dialogue. Everything else behaves normally (they take endless amounts of gifts, they return home, they do spouse things).
Its currently Winter, Year 1.
@pine lynx