"...polyamory can be nothing short of a fancy name for having hurtful affairs..."

This right here sums up it up for many couples. My GF of five years wanted to open our relationship and it was a deal breaker. She cited her friend's poly-marriage "working" and I said this exact thing. It was 100% the husband marginalizing himself to keep her. The dude drinks too much and looks like he wants to jump off a bridge. It'd be one thing if we started off poly but there's no way I can deal. Call me old school but if I'm the one helping care for her dying Dad, looking for her drunk son at midnight, holding her hand as she's wheeled off for thyroid cancer, etc...then it's a hard Hell No if she wants me to stick around while she sleeps with someone else.