Marriage and commitment really became desired due to how offspring were able to survive and thrive better if they grew up with parents. We often forget that children often failed to make it to adulthood. That is often why so many ended up having several children as not all their children survived into adulthood. We forget that it was not all that long ago that parents often faced the loss of one or more of their children due to all the diseases and illnesses we now have found vacinations for as well as antibiotics and other medicines that can contribute to a child reaching adulthood. Now what was once common is considered a major tradgedy when someone experiences the loss of a young child.