Him (28M) and I (24F) were at a work event of his. Nearly every coworker he introduced me to as his girlfriend but one young female coworker and another woman (probs late 20s, early 30s) who was the gf of his manager. (Which made me uncomfortable). At one point the gf of the boss, him & I were chatting all together & he offered to buy her a drink! She said no. Then she asked me at one point “how do you know each other” and I said “he’s my bf” and she came across as surprised. I walked away at one point bc he was drunk laughing with her. I felt both embarrassed and furious. How should I confront him about this?