To unlock the ability to get married you have to buy the Amulet of Mara from Maramal in the Bee and Barb inn in Riften which is in the south eastern part of the map then equip the amulet then just talk to a girl/guy and whabam you can get married
If you have what happens to me where some random body pops out of no were and stops the wedding then go to your house and wait or sleep a couple times. I did that and the body appered in the house and then i could get the achievment.....and married which is cool too....
Not sure if it was a glitch or actually part of the game's programming, but it kept saying I failed the quest everytime I contracted a disease, got poisoned, or if my follower was incapacitated in a fight.
So much for adventuring for a wedding gift before the ceremony. Thought a nice deadric artifact would've been a good show of affection, like Azura's Star or the Ebony Blade...
