The Day After

Uhm... who's that person who you just woke up beside? Broken cocktail glasses on the floor, flowers all over the room, and why the heck are you wearing a ring? Yesterday must have been a long, weird day...

Obtainable by getting married while being drunk. Note that you must be drunk during the entire ceremony, and you got to be the second player saying 'hi' to the NPC in order to get the achievement.