I guess the way I’m thinking about it is that just because the third party doesn’t know it’s poly, doesn’t mean it isn’t poly to the people in the primary couple. It’s unethical and dishonest, but it is a situation where some of the people involved are being non-monogamous.
I mean, yeah you can do polyamory in an unethical way. But it isn’t really polyamory if the poly part is a secret to the people involved.
I guess the way I’m thinking about it is that just because the third party doesn’t know it’s poly, doesn’t mean it isn’t poly to the people in the primary couple. It’s unethical and dishonest, but it is a situation where some of the people involved are being non-monogamous.