He may not even start your wedding due to a bug. To fix this type into the console: setstage RelationshipMarriage 100, this will marry you, even though your spouse will not act like it. Then type in: removefac 51596, player.removefac C6472, resetquest 74793, resetquest 21382, setstage 74793, and then wait 24 hours. (can be done by pressing "T"). This divorces you. Now, you can get married again and Maramal should start the wedding.
He sometimes will not sell the Amulet of Mara, even after exhausting all dialog choices. Be sure not to have an Amulet of Mara in your inventory before trying to buy the real one for marriage. However, this is not necessary as there is no difference between Amulets of Mara and there are no points to buy one if you already have one. You can use a looted, pickpocketed or stolen Amulet, too.
There is a bug when you try to speak with Maramal about arranging your wedding that causes him to disappear from all locations within Riften. The quest marker within Riften will lead you to a wall, and the map's quest marker says he is located next to Merryfair Farm.
It is possible for Maramal to not spawn at all. He is nowhere in the world and there is no way to talk to him without restarting your game or by the use of console commands on PC (Such as "player.placeatme [character base ID]")
If you killed one of your followers at any point in the game, their body may spawn in the building, with everyone acting as though you just killed him/her. This will result in Marmal yelling "Get out!" whenever you approach him for the rest of the day.
If you did not arrive to your wedding on time Maramal will shout "get out" just fast forward one day and ask him again after asking your wife to re marry.
He sometimes does not move to the "Temple of Mara" after you buy the "Amulet of Mara" from him. The only time he enters the temple is when you are getting married. Afterwards he will go back to the "Bee and the Barb" (PS3)