That’s the sunday school version of marriage.
The #1 reason why people get married is parenthood. We don’t know who dad is. So the only way in ancient time to know who daddy is if to have the wife commit to fuck only one guy, namely her husband. You see why most cultures, like biblical culture, allow polygamy but does not recognize polyandry? Polyandry has no points. We know who the mother is. You don’t need marriage to settle inheritance in matriachal culture.
Before only rich men with inheritance need marriage. Paternity assurance means a lot to them.