I'm just re-reading Engel's "The Origin of the Family, Private Property and the State" and can't be but delighted on how accurate it is on so many aspects.
One of those is the role of love in relationships. Perhaps you already know it but love didn't play a major role in the ancient times. Relationships were more out of convenience than anything else. They were mostly for breeding children and having a semi-stable environment where companionship and practical support were the top values. People wasn't necessarily attracted to one another at the beginning; they developed feelings over time not very different from the kind of friendship developed by solders during armed conflicts. Just sexual.
I say this because it seems to me like like nothing has changed significantly even today. I was reading some forums and I'm impressed to read how many people stick to shitty relationships just because they feel like they can't go anywhere else. There are women who even go as far as posting ads offering to become a stable lover in exchange for financial support.
My hypothesis is that liberty in out world is just an illusion. We're still slaves to the system, it's just that we're locked using a different kind of chain: money. And I've come to the conclusion that any relationship where money plays any significant role is probably not a healthy one.