So I am coming at this from a irl perspective. I have 2 old friends.... no. I have one old high school friend and a former HS classmate that I am FB friends just for the delicious drama.
The friend is in a stable 6 person poly group that really works because none of them are bound to each other. They live in several different abodes, some shared, and balance spending time with each other vs adulting.
The drama boy is a effing con-man sleaze who convinces women that they love him and that open relationships are 'teh way'. He then leeches off of them, one at a time and moves from house to house to keep them from realizing he is such a bum. Until he messes up and has to do damage control to keep one angry woman from burning down his little scam.
Fiction wise, most are really bare bones slock without any effort put into fleshing out the members as more than just checkmarks to fill a kink list, ala Smartphone.