How would you react to a friend trying to sabotage your relationship?

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I've recently learned that a friend I've had for almost 20 years has been trying to sabotage my current relationship. She and I have always been close since the day we meet in Junior High. We've always had the same tastes in boys, music, clothes, everything. She was my long-lost sister that I never had. I've always been the follower during our school years and as we grew older I become my own person and found my place in the world. Which didn't necessarily mean right next to her. However, we have remained close and now I'm having a hard time figuring out how to deal with the current situation. She set me up with a man from her work about a year ago. In the beginning she told me how perfect he was for me, how she just knows he is the one for me. I had reservations at first, picked out every flaw I could see, and told her I didn't want to date him. She convinced me I should at least give it one date. So, I did. She was right. He was perfect for me, we had so much in common, yet that perfect balance of opposing views to keep things interesting. Then, about a month ago, we had a get-together at her place. The guys wanted to watch something sports related on the TV in the background while the ladies conversated. She wasn't going to have it. My man and her man decided they would watch it anyways, despite her protest. Ever since then, she has been telling me that my guy is not for me. She's pointing out all those flaws I first saw, trying to tell me that all the little things that I've complained about over the last year are too much for our relationship to work. You know how friends get together and just vent, well now she's using that against me and telling my man all these things that she is blowing out of portion, when maybe I had a bad day. My man is great, he's one of a kind. He's come to me and told me all the things she's saying to him. They are basically the same things she is telling me about him. I don't know why she doesn't think that we would talk about all of this together, but I almost wonder if she's not trying to get us to quit being friends. Maybe she's not sabotaging my relationship with my man, but with her? So, now here I am, trying to figure out if I should dump a friend after 20 years. There have been other spats between she and I. Ones about not going to every function of hers, or me not spending time with her as much anymore, etc. But those things don't really bother me because she has a few different circle of friends that she hangs out with everyday, so it's not like she missing out on anything in her personal life. What do you think I should do?