she's the outsider........per se. I wouldn't let it bother me if I were you. We girls do the same thing here.
If a guy from my race were to go out with *another kind* be it white, black, green or blue, it's not from MY race. Especially if it's one that is a *good/great catch*, the women are probably jealous, as we would be ... *What we weren't good enough that he had to find someone not from here.....not Hispanic.......not whatever*.............
It's a girl thang...........unless they say something verbally, walk with your head high, shoulders pulled back, and let her (your girlfriend) know how much you absolutely adore her