WHY MARA? WHY? HAVE YOU CURSED ME? Yes... When I was going to marry someone and I went to the chapel I waited. And I waited. For them to come. They came, and when they came it said FAILED: Attend your wedding ceremony.......... I tried a hundred times, and with different people! Do I need a ring or something? Or is my game just bugged?

2 things

a) I think generally marriage has a nasty bug in it. But the good news is after the failure, you can ask the betrothed for a second chance and a second ceremony (worked for me on second try)
note: You must wait at least a full day before the priest of Mara calms down..

B) When you get the failed marriage, did a corpse just show up at the entrance ? if it did, you need to drag it out of sight (I dragged it downstairs in the temple) before I re-attempted

Woila, marriage completed..