Feeling weird that my (22M) gf(20F) is looking at guys for her best friend(20F) while I’m around or even when I’m not around. Should I be worried about it?

My gf’s best friend is a very lively party person when she’s single. When she’s taken , she never goes out or parties. When the three of us hangout they talk about guys and look at them. Recently I confessed to my gf that I’m not comfortable with her looking at other guys , she bursted out at me and told me that she just wanted to look who her best friend kissed, it’s not a big deal. Personally I have never been to night clubs until recently where her best friend invited me to a “bar” which ended up being a night club instead. When I went in , the best friend started making out with a guy in the first 5 min in. Then she asked me to go dance with her and I gently denied as I was a bit tired. Her best friend came back making out with another guy in front of us.Me and my gf had a bad experience with a guy that came to me and asked to fight in the parking lot which I shrugged off and told him walk away. Then I left the “bar” and went outside and asked my gf to go home with me. She denied and said that she had to wait for her best friend. When we were waiting outside to get into the “bar”, her best friend was showing her all the guys she has kissed and my gf started looking at them, I didn’t say anything as I did not wanna come off as insecure. But my gf was really looking around in the line back and forth for all the guys. Now everytime I try to bring it up and tell her that I’m not comfortable , she says that I’m an asshole and if her looking at the guys bothers me I should breakup with her. Also brought up that she showed a picture of me to her best friend when we started dating. We have been dating for 2 years and I honestly don’t know what to do. What should I do in this situation and should I be worried for these behaviours?