Hope this isn't too much of a power-level, but relevant story:
Years ago I used to hang in a friendship group that overlapped with some polyamorous groups, which means I attended some 'normal' (i.e. not for hooking up) parties that some polyamorous people attended too. They usually have extensive social lives because they are constantly on the lookout for new
victims people to recruit into their insane ways.
Once, at one of these normie gatherings there was this divorced, polyamorous forty-something guy who brought along one of his girlfriends
and also his teen daughter. She was the only child in attendance and definitely old enough to stay home by herself, which to me screams he brought her along because it was his weekend with her and knew he shouldn't leave her at home. Or maybe he wanted to play the 'cool dad' with her

. He then proceeded to spend the whole party flirting and taking uncomfortably close up portraits of women much younger than himself and his own girlfriend, and also ignoring his own daughter (to whom people were very nice because everyone felt sorry for her). It was such an obviously inappropriate situation that people talked about it for a long time afterwards.
I remember the daughter seemed so serious and detached, acting older than her age and like everything was normal and cool, obviously coping with her weird life as best she could. She must have already been so, so screwed up.
Also, during the party the girlfriend was unnaturally cheery and acting all 'everything is fine' when it obviously was not. She was also terminally on Twitter, clearly very insecure, and ended up breaking up with this guy some months later.
Anyway. There are other cases I know in which polyamorous people go to normie parties to creepily try and get laid while their spouse stays back home with the kids, which to me is also fucked up, but at least they seemingly keep things separate. Involving your children directly in your shenaningans is the worst of decisions and will destroy any healthy boundaries the children might have, which will have very damaging and lasting consequences for them. Not that these people would know, having zero boundaries and self-respect themselves.