You mentioned that you plan to ask her not to talk about him around you. That would be a *big* signal to me (if I were her) that you had a problem. If I were your girlfriend, I would rather you do me the courtesy of talking to me about it openly. Passive-aggressive attitudes (and that's how I'd perceive it) tend to turn me off considerably.

IMHO, telling her openly says "strong, confident man" to me...which is good. Stewing about it and saying snipey things about the guy says "insecure and jealous." Which one would you rather be?

What's the worst that could happen? Your fears be confirmed? Wouldn't you rather know sooner than later if it is true -- that she likes him? I know I would.

__________________
Life is too short not to love and be loved....preferably multiple times in one night.

I think men talk to women so they can sleep with them and women sleep with men so they can talk to them. ~ Jay McInerney