Marriage in the Amish church requires membership by baptism
Due to the structured nature of Amish culture, allowing mixed marriages would threaten to destabilize Amish society. Most Amish youth become baptized between the ages of 18-22, after which they are likely to get married.
In rare cases, an outsider may join the Amish in order to get married to an Amish person. Amish do accept converts, though they generally do not proselytize or encourage outsiders to join.
It has also occasionally happened that a married Amish individual has left the faith while the spouse has stayed behind.
Read more on Amish marriage.
Photo credit: Garret/Kitty Wilkin