Yeah, ridiculous to think that people wouldn't hurt or feel the sting of a break-up anymore if they embraced polyamory as their "true nature." Polyamory is about love, after all, not just biological sexual urges, and loving someone brings the possibility of a full range of emotional responses. We let someone into our hearts, and when they move on, there is often pain, for numerous reasons. Plus you don't know what happened with that couple to make any assumptions.
Hey, regarding DNA coding and biology and choice an all that shit, think about this: I'm biologically built to birth babies, but I've never felt the urge. I may be programmed for it, my hormones and instincts prepare me for it, but I know I was never meant to be a mother. I never wanted it, and at 50 I am relieved and happy to have dodged that bullet all my life. Am I missing out because I have a uterus and was supposed to use it for popping out offspring?