I always thinking why people not like to have multi lovers more than one partner? (I mean of course every member realize the existence of the other) I don't talk about cheating, and I don't talk about threesome sex or whatever I talk about love and marriage. Here in Middle East the old generations and some new generation manage to live with male marring two wives without any problem, even old Christian and Jewish generations had that. but my problem with that kind of marriage is the male who allowed only to love the other female partners. so if we humankind successful with that kind of marriage why not take the next step and have multi partner marriage or love between all of them like two gay love with one straight love with the female, or two lesbian love with straight love with the male. ..etc. specially now we have enough sex freedom to do that I talk about of most the people excluding of course my people (Middle Eastern). Excuse my poor English language.
Polyamory: the practice of engaging in multiple romantic (and typically sexual) relationships, with the consent of all the people involved. It's increasingly common. Marriage is essentially a legal vehicle to facilitate the intergenerational transfer of property. In places where the population has become less interested in religious practice, and in places where people have few children, marriage is also becoming less common. Polyamorous arrangements are more openly acknowledged and respected where I live than ever before. It's not for everybody, but between consenting adults, it can be very satisfying. That said, they are difficult to manage. Even in the Middle East, and old saying goes that four was the correct number of wives for a man to have. If there were two, he would constantly find himself in the middle of their disputes, and at least one would end up very unhappy. If he had three wives, two would always be ganging up on the third. He needed four. Yes, difficult to manage indeed.
On any kind of scale polyamory ends in disaster. Very few people, as in single digit %'s, can maintain a loving life relationship with someone while having secondary relationships at the same time. It is silly to think otherwise. Not to say there no people who can. There certainly are. But they are a small minority.