Originally Posted by YamZenitram
Am I overreacting? I don't want to make waves for no good reason, especially since this is our first time out there. I don't want Stephen to think that I'm only doing this because I'm jealous, or because I changed my mind about polyamory. Should I leave this decision up to Stephen? In your opinion, when is it okay for the "other" partner to intervene?
Well, at the end of the day the decision is up to Steven; you get to ask him whatever you want, and he gets to decide what he wants to do. But I think that the answer to your questions are relatively straightforward. You have totally legitimate concerns about your partner being involved with someone who is proven to be dishonest, and is explicitly not interested in being in a poly- relationship. That's a pretty bad choice in someone for him to be involved with! I think you kind of owe him your honest opinion of the situation, and you convince him that it is not jealousy speaking by not acting jealous when you express that opinion.
I don't think it matters very much whether or not this dynamic is "really poly-" or what her motivations are for lying, or how great a connection that they might have. At the end of the day, your partner being with a jealous, dishonest person in any kind of relationship is really problematic, and not speaking up about it doesn't do anyone any good.