people flirting w s/o in front of you

Has anyone ever dealt with someone being a flirt to your man in front of you? It’s so awkward and so inappropriate.

It’s happened so many times and when I tell my boyfriend I don’t like it he gets mad at me. Yet if someone does it to me and I just ignore it it’s an issue...

there have been countless times where we have gone somewhere like we went to pay a bill and it was under my name etc. the girl ignores me and talks to my boyfriend the whole time and asks where he lives and how she loves his restaurant etc and ignores me like I’m not even there. It made me so uncomfortable. We have been together for four years... like there’s a fine line between being nice and completely just ignoring me.

Maybe I’m over reacting idk :/