Date or Dump?

So long story short me and my friends ex caught a movie tonight. He's soooo easy to talk to and is smart and funny and it's just great. But he's my friends ex and I also went with his friend for awhile. So I get home from this awesome date and decided it's a good idea to tell my friend. Because you know I'd want her to tell me. Now mind you she has a boyfriend of almost a year and my guy and her have been apart for 3. So my friend flipped out on me. How I shouldn't go with him because they were together. I can't reason with her and I don't really have any other girls I'm close with to talk to. Do I end it with the guy to keep my friendship or pause the friendship to be with the guy?