By the way, I checked the National Geographic Style Manual this morning:

COLLECTIVES AS SINGULAR OR PLURAL

"Collectives (family, team, couple, etc.) tend to be plural when the component members are considered separately and singular when the group is handled as a unit: a score were present; an army marches on its stomach. The plural often prevails when humans are concerned: The couple are..." But then it goes on to say: "The decision between singular and plural is frequently writer's choice."

In this case (a wedding), I'd tend to view the couple as a unit!