I always bring up the ethical non monogamy because it’s the most objectively insane thing. It’s so obviously toxic and unfair.

Seems to me you’ve only found bad examples of ENM. For me, a relationship is about honesty, communication and wanting the same thing (except BDSM). If people are lying to each other or don’t really want the same thing then it’s not really a good relationship and should end. That’s most relationships really but that’s human nature for you.

The few ENM couples i know have near perfect relationships because they’re pretty clear with each other on want they want, and they want the same thing.

I get that women get a free pass for a lot of bullshit they do because they’re women and how dare you, you’re sexist and See? it’s the patriarchy but i’d wager most toxic behavior is 50/50. Humans are assholes regardless of gender.