The whole reason for marriage isn’t to create children—that just requires functioning junk and a will to apply it—it’s to formalize issues of social and economic alliance between individuals and/or family groups.

If marriage were really just about procreation, then there wouldn’t be any variants like polyandry or polygyny, nor societies in which marriages is a temporary and/or renewable contract, nor societies that conduct marriage rituals between individuals incapable of reproducing.