The superstition for why does the groom stand on the right side dates back centuries. The following explanation is by far the most popular.
The tradition actually stems from the old days of “marriage by capture”, where some tribes had a shortage of women and tribesmen would go to neighboring villages and steal a woman. Even in those primitive days, wedding ceremonies were held.
The groom needed to leave his right hand (his fighting hand) — which he used to hold his sword — free in the event that tribesmen from his brides village, would attack to try to get her back..