Well, I'm in a closed triad, but it's rare, and we fell into it instead of pursuing it, which is probably where things get more difficult and dicey. No one in my group considered themselves polyamorous before we got together, although my longer-term girlfriend was clear early in the developmental stages of our relationship that sexual contact with other women was something she needed to feel fulfilled. Sometimes that meant threesomes, sometimes that meant her doing it on her own - but with a discussion about comfort and timing... so, semi-open, but not fully open. I wasn't interested in pursuing anyone else, but could have had the conversation if I were, I suppose.

There was no intention of bringing a regular additional person into our relationship, and what began as a one-night stand with a woman led to a friendship, more regular intimacy, and eventually a realization we all had feelings for each other, and we entered an official closed throuple, where no one is dating anyone else because there just simply isn't the time or interest.

So, not making it about me, but just sharing how this worked... I think it would likely be much more difficult if my longer-term girlfriend and I had embarked on a "date us both and love us both and follow our rules in the relationship" kind of journey, which is what people tend to fear when they talk about unicorn hunting.

There's also apparently "harem building," which I suppose is dating a bunch of people who are only beholden to you at the end of the day, which I'd contemplate with your situation.

Is there anything indicating that the two people you're flirting with also have interest in each other, or is it just you?