I agree with Lisa and Mary. I'm sorry it happened but hey, people are azzes sometimes. I had a similar situation at work. I was expected to go to a baby shower for a person who had been spreading nasty and untrue rumours about me. I talked to DH about it and he told me to go, dress to the nines, be happy and have fun. It was the best way to get payback because she was blabbing out of boredom with her own life and I was showing her how much I was enjoying mine. And all the people that really mattered that were there knew that what she said was BS.

I hope you go.