What to do

My best friend (girl, about half my age) and I was on holiday a couple of years ago, in Hurghada, Egypt. One night, we were both drunk, we went into a bar, it was empty, but two staff guys. I later read guys there are whores, really. My friend went behind the DJ booth, and one of the guys stood behind her. The other one tried to distract me. Then I saw her reaching back for the guy's cock, and it was apparent he was putting it in her ass, stroking, or groping. I didn't know what to think or do, she was not my girlfriend, so... After a while we went away. I also believe she had a quickie with a tattoo guy, in a booth, but I'm not sure. She later has had sex with other guy's, but she won't have sex with me. Shall I leave her, or hope she changes her mind? I really want her, she's hot as hell. What would you do?