Most religious groups when there is an intermarriage allow fast conversions, Like Muslims, there is no intermarriage with muslims because they simply convert the non-muslims partner (even if they really dont believe)
I think generally christians take a similar stance, however in recent yeats when there is an intermarriage they dont force anyone to convert (Dont kid yourself while we might think Methodists and Catholics are the same christians, they do not think the same, A methodist marrying an Catholic is a terrible thing in both sides eyes)