I had a girlfriend who was fucking a guy in front of me without me knowing at a club. The bar, where she was sitting on a stool, level was black lit so making figures was hard. I started yelling to get out while grabbing her arm. She responded, " I wouldn't do that now if I were you. I look behind her and some big shadow was right up against her. She didn't say anything for 20 seconds carrying a concentrated look on her face. At which point she reaches back, kisses the stranger in the cheek, and walks out with me.