When I started branching out as a sex positive activist, one of the first workshops I took was on polyamory. I didn't know at the time, but the workshop ended up being very heavily focused on how couples could pull out of the driveway of monogamy and enter the streets of polyamory. This workshop ended up focusing a lot of energy on unicorn hunting, and as a trans woman who mostly hangs out with leatherdykes, it didn't sit well with me.
I am polyamorous. I identify as solo polyamorous, which is a type of polyamory that centers myself in the relationship and mostly does away with hierarchies (primary, secondary). As a solo polyamorous woman, I'll occasionally get couples asking me to go on a date. My answer is always no. I never date couples unless they're paying me. I also tell single poly women to never date couples, and those who don't take my advice have always regretted it.
I'm not against the idea of triads. If I'm dating someone who meets one of my other partners, and they fall in love, that's great. What I am against is monogamous couples who make a set of rules to preserve their relationship, don't allow the third person to consent to, or sometimes even know about, the rules, then go out and hunt their unicorn.
In unicorn hunting relationships, there is almost always an inequity. Just by the unicorn being the "third" it places them at a status that is unequal to the initial relationship. What if she doesn't like your partner? What if your partner doesn't like her? Who gets left for whom? Those rules you made to preserve your relationship end up arbitrating the life of someone who never got to participate in their formation, or agree to them from a position of equality.
But what about people who like being unicorns? Yeah, that's great, go to an orgy or a swingers party where you can explore that with people who consent. The fact is, though, that unicorn hunters don't just do it with people who consent, they often create a dating profile using the woman's photos, and don't disclose their couple status until after they've wasted the time of a bisexual or lesbian woman.
If you are a couple and you want to open your relationship, do it, but do it in a fair way. Don't make rules for someone who can't consent, and if you're hunting a unicorn, go to a place where unicorns are consenting to being hunted. Ideally, you should just date separately, and if your relationship can't survive that, maybe polyamory isn't for you.
To paraphrase a friend, a unicorn isn't something a couple hunts, it's someone that they run over as they pull out of the driveway. If you want a third to spice up your relationship, consider hiring a sex worker. If you want a third to teach you about kink, or to coach you on gender affirmative intimacy, feel free to send me a booking request .