Originally Posted by kdt26417
With the level of friendship you have with this person, perhaps the general topic of polyamory will come up eventually.
Yes, this is a good idea. You could say to her, "Have you heard of polyamory, where people are involved in multiple, ongoing love relationships? I came across some interesting reading on the internet about it. [Girlfriend] and I were talking about it and I find the whole concept of having more than one partner intriguing. It's about emotional involvement, not just sex. What do you think about that?"
If she's totally turned off by it, you know where she stands and it looks like just a philosophical discussion. But if she's uncertain and willing to discuss it, or excited by the idea, there could be some possibility and eventually you might be able to express your attraction to her.