If we really want to get into it, "traditional" marriage was far more about the acquisition of property than it was actual procreation. Children were too considered a property.
In a traditional Western marriage (as in, from the last 500 years or so), a marriage granted:
- Rights of the husband to the wife's property
- Right of the husband to the wife's children (also considered property)
- Rights of the wife to have her children someday inherit her husband's property, upon his death
- Rights of the wife to some of her husband's property on his death should the marriage be fruitless
The reality, especially among the upper classes, was that not all the kids a wife had really were her husband's, but by the property laws, he was obligated to treat them as such unless he had rock solid proof of her infidelity. In exchange, he could pretty much do whatever the **** he wanted with the kids. Abandon her and take them to another country? Sure, why not. Beat them senseless? Short of homicide, it was allowed. Legally, the wife had no say in what he did with them, or with her, so long as he didn't kill them or violate laws.
The very fact that we no longer view any children born of a marriage as the husband's property to do with what he will (nor the wife for that matter) means we've already changed the view of "traditional" marriage radically in the last hundred years.