Is my friendship cooked?

So I have my bestie, known her for more than 6 years now. We've been trough thick and thin I really love her but I have a huge problem. Whenever we go out together she literally can't go without flirting. Multiple times she started talking with a random man and I just stood next to them waiting for her to finish. And sometimes the guy sticks for the whole night. So when she recently asked to go partying, I straight up asked her to not dich me for a random guy she sees right after we arrive. Response: oh yeah ofc I want to have a girls night too! I wasn't even surprised when 30 minuted after arriving she started dancing with a guy. The whole night I felt so alone I tried to also dance with a guy but it was not what I came there for. She also disappeared for like a hour. And after the party she said that she's sorry but she felt an 'emotional connection' with the guy. While mind you she's allegedly super in love with some other guy from uni. How the hell do I explain it to her that this is not okay??