I'm 50 and I've been single most of my life, married as a teenager only because I got pregnant by a horrible man and got out of that ASAP. Not a marriage.

To your points about exclusivity, poly, monogamy and the harsh statistics my perspective is that relationships fail miserably because people don't develop the most important quality that is necessary to make any kind of relationship harmonious - maturity.

People go their whole lives unwittingly developing bad habits from a lack of maturity and end up doing stupid, selfish things. In business, "romance," friendship. Self-centeredness is the hallmark of immaturity. It is not a foundation for communication, sharing, mutual respect and intimacy. I wrote a post recently relating to this something about the most important thing I ever learned about relationships.

I love this topic, thank you for this post.