I’m married to a man and poly with a woman as well. We just started dating and she said she told her best friends about me and my lifestyle and they freaked! They told her she is going to get hurt and that she should find someone else. I don’t know what to do without having support from the closest people in her life and I don’t want to be seen as a flight risk just because they don’t understand commitment and polyamory. I have no idea how to meet these people eventually without feeling hurt.
This is not actually an actionable problem for you right now. Some people you don’t know, but who know someone you’re close to, are being ignorant. There’s nothing you can do, or should try to do, about that.
Be there for your partner - she’s dealing with the pain of being judged and rejected by her friends. If she asks, help provide her with resources about coming out as polyamorous, or ways she can explain to her friends that what she’s doing is healthy and consensual. But if she doesn’t ask, leave the topic alone. Don’t try to argue with her friends through her.
She may be believing these people, and worrying about the security of your relationship with her. Do what you can to reassure her, through words and actions, that you are safe and committed. Answer her questions when they come up. Don’t get defensive or act like it’s her obligation to either change her friends’ minds, or shut out their opinions completely. Be open, reassuring, and loving.
There is a chance that if these people are adamant enough or close enough to her to be convincing, she could get freaked out and wants to take some distance or leave the relationship, that will be frustrating and painful for you, but even though she’s acting on wrong information that other people are telling her, it’s her choice to make.
Don’t worry so much yet about meeting these friends of hers who you know don’t approve of your place in her life. It doesn’t sound like she’s pushing for that, or like you’re all about to go on a cruise together. If you’re at a social gathering with them, be charming and sweet while keeping enough polite distance to protect your own feelings.