I don't have a boyfriend for girls to flirt with, but I do have a sort of... crush. There's at least one other girl who I can tell likes him also, but I'm not worried about it because he doesn't care for her, as far as I can tell. I dunno...what's the point in getting all upset and whatnot? I think it's crazy how some girls can get so cut throat about it. If I had a boyfriend and some girl started flirting with him, I'd just hope that he loved me enough not to flirt back with her, or some how show her that he's with me, like taking my hand or if they were talking, some how say, "Have you met my girlfriend Amanda?"
But yeah. With a guy that I like and am not with, it's not really like I have a claim on him so I don't have the right to really get upset if other girls flirt with him I think. They have every right and the same as I do to flirt.