Monogamous relationships are only a recent cultural invention and as the ratio of divorces suggest — not a very successful one. Love is also a very recent invention. People in the past had marriage for business reasons. Love was considered an immature tendency that teenagers had. They understood how ephemeral the whole process was and thus they kept their distance from risking the entire lives towards it.

Ok, you don't know anything, here's a wiki link to start your journey on what the fuck love is, how long it's been around and if it has anything to do with marriage or a covenant between two people and exactly what it means. Love isn't an invention, People in the past didn't have relationships and start families together for business reasons, that is wrong, people struck up friendship and relationships ensued which gave birth to families and it all happened because of love not because of love for money.