YTA... you say you trust her... but you actually don’t. If you did, you wouldn’t care if people flirted with your GF (cause you wouldn’t have anything to worry about).

Not only did you embarrass yourself by coming off as insecure, you embarrassed your GF by showing her barista that she’s dating an insecure guy with the social skills of a caveman.. I’d be embarrassed too.

Also, just because you’re in a relationship, that doesn’t give you the right to dictate how other people interact with her. She can do that on her own (maybe because she’s an adult?) — and unless she asks you for your input/help/is in obvious danger, you mind your own business. If you have a problem with one of her relationships, you talk to her about it—not the other person. She’s not your property and you’re not her guardian. Having a significant other means you’re in an equal partnership — not a master/slave relationship.