WITH reference to your article on polyamory: I am assuming that a person goes into a serious relationship based on love because they are looking for something stable and secure rather than fleeting first dates and one-night rendezvous.
In this stress-inducing world today, we would want to return home to a comfortable, safe cocoon and enjoy the company of our loved ones (whether they be spouse/kids/pets). Many would call this a happy life. Given this definition of a happy life, neither monogamy nor polyamory/polygamy/polygyny can ensure that we achieve it.