AnnabelMore has given you some great points Cloudy and I really hope you read the links she suggested, it is a shame you bristled a bit at Boringgys posts as just a few days ago Boringguy posted this exact (and I am not exaggerating) scenario of a new person coming onto the boards and putting forth their great idea for a totally equal triad as if no one has ever heard of it before and sadly.....we have indeed seen it 1000 times, some of us have experienced triads and trust me, the first few awesome sexual experiences do not make up for the complexity and added stress of a triad, eventually the awesomeness of the threesome fades as well and you'll eventually want to have more dyad (twosome) sex. Think it feels awful being left out when your 'one' partner has sex with someone else? How about when two partners leave you feeling that way?
Trust me, it doesn't do to have a hearts and flowers idea of triads.
Keep reading both here and on other sites and you will see the same stories all over the place. Look at the 'Dating and Romance' section of this site and see all the non responses to the posts from couples 'Looking for our third' and you would realise that all these people are here trying to do the same thing you want, with little to no success at even getting a single person to respond to them.
Finally, I think you might want to separate your g/fs bisexuality from her Polyamorous nature, many couples come seeking out the Hot Bi Babe because the female is bicurious or really wants to connect with women. The triad is their way of doing so whilst still feeling safe and protected within the couple because the man is involved too. However, someone who states that they are Polyamorous and wants to be able to see both men and women would unlikely be comfortable with being confined to one gender because it is more than just about sex for her, it is about the freedom to make connections freely.