She Kissed Him. I Left with Her Friend

My girlfriend kissed another guy for a dare—and told me I was overreacting. So when her best friend drew "take a guy home tonight" and held out her hand to me, I said yes. Right in front of everyone. That night, my ex blew up my phone. She was sure nothing happened. She knew me too well. But what she didn't know was that Vivian's apartment was right above the bar—and I never left.