Sadly, there are those who behave in aggressively entitled ways and are over the top offended by any response that doesn't validate them, even at the expense of the community. I've encountered this dichotomy a few times in my adminning of WE PAW. It's always unsettling. We play the encounter over and over in futility.

It sounds like you engaged considerately and with kindness, and with the community in mind too. You really couldn't have handled it better.

I feel like someone who's fetish is cheating would not be a good fit. Polyamory still requires consent and understanding between partners. Cheating is betrayal and disloyalty, and goes against consent.