A happy spouse might make breakfast, feed animals, repair fences or water crops.
They occasionally change the wallpaper or flooring of the Farmhouse.
The wedding ceremony takes place in the morning, 3 days after you propose.
That is, if you propose on Monday the 1st, the marriage cutscene will take place as soon as you wake up on Thursday the 4th.
The wedding ceremony does not take place on a day that another event takes place in the town square.
When the ceremony is completed, you and your spouse appear at the farmhouse at 6am (on the porch, or if you have restarted or reloaded the game day, inside the house).
The day then proceeds as it normally does when you are married.
There is no friendship penalty for giving bouquets to dating rivals, though there is a Group Heart event that may cause all girl/boyfriends to give you the "cold shoulder" for a week.
The day after reaching 10 friendship hearts with a marriage candidate, you will get a letter from Mayor Lewis: “I'm going to give you this advice because I like you and I want you to stay in Pelican Town. You can find him on rainy days at the tidal pools on the beach (across the bridge you repaired).