Should I end the friendship?!?

My girlfriend, let's call her lexis, broke up with me on sunday (6 days ago) my best friend, lets call her angie, and she sort of liked each other, but lexis asked me out instead and angie said she was totally fine with it and that I was better for her anyways. Last night, however, (friday) my friend slipped that angie and lexis were dating, and I flipped out and she was like oh no wait sorry I'm getting my dates mixed up sorry. And I was pretty freaked, because I'm still not over lexis, and i asked angie that night and she said it so wasn't true and that my other friend was tripping balls. Today, I was will another friend, margot, and she told me lexis had told her the day before that she and angie were dating. I flipped out. Not only is my best friend dating the girl I'm not over behind my back LESS THAN A WEEK AFTER SHE DUMPED ME, she lied to my face about it. I think I have much higher standards than to continue my friendship with her, because that's awful. Let me know!