Help

Made a mistake 14 months ago in my marriage. It's a mutual friend of my best friend. My best friend knew about it, it was 1 time. Months later she started a full on affair with this man. He manipulates her to the point she tried to end it 4x. She finally did... Now she accuses me of sleeping with him.i am not ... I don't know why she feels I am. She called me and I sobbed because after all the pain he caused her including separation in her family why on earth would I do that? I'm hurt and angry as hell. To have lack of care or judgement of my character. My text message from her said not to try to come back in her life and hope he was worth it. I am distraught and flabbergasted ....