I smell a rat, and I don't like it.
I'll put it this way: when I'm dating a girl, I make it a point to not comment on how attractive I find other girls. Even if it's a famous movie star and my girl asks me "so, which of these 3 movie stars do you find attractive?" I don't answer the question. Not because I don't find them attractive, but because it's RUDE to tell the woman I'm dating that someone else is pretty - it doesn't help your cause for her to know this info, and can only end up lowering her interest level.
And so, the opposite is also true - if I see a girl I'm dating talking about how cute or handsome she finds another guy, I take it as a sign of disrespect. Do I let it fall by the wayside? Of course not, but I don't wine about it either. I'd just point it out to them ONE time - i.e. "Hey, I'm not sure if you know this bothers me or not, but I'd really prefer it if you not point out other guys you find attractive - I'm not gay, therefore I don't really care" - and that's it. If they keep doing it after that, I drop em. However, as weird as it may sound, the logic of not pointing out other guys' attractiveness is sometimes lost on girls - they can have guy friends and/or look at other guys like a piece of artwork without wanting to do anything with them, so oftentimes they don't even know it's bugging us.