re: The culture difference . . .
Would that be more like beating a woman for walking outside without being covered from head to toe, or more like the culturally enshrined practice of female circumcision?
Forcing children into sexual relationships is wrong. Tradition is no defense.
Tradition has been used to defend all sorts of atrocities. Domestic violence is only one of them.
Forcing children into sexual relationships for financial reasons has a name. It's not a complimentary one.