What should I do if my girlfriend is flirting with another guy

Well, if it bothers you, mention it. If she's doing it to get your attention, let her know she's got it. But maybe it's possible she didn't know she was flirting? I mean, I have been accused of flirting when in my mind I was just being nice and doing NOTHING of the sort. Communicate! :) Flirting is flirting, for the most part, it's harmless.

If her flirting upsets you then you need to point this out to her. Maybe she doesn't realise, in which case communication is the key.

There are a thousand reasons as to why she may be doing it, but I wouldn't jump to any conclusions until you have mentioned to her that you aren't comfortable with it and she needs to real it in a little.

Never get worried about anything and ifyoudo decide to say something make a firm pointof it do not back down do notbe controlling just state your points and explain your not interested in people who behave in that way..

Either way be ready for what you may not wish too hear. Be strong take no crap you don't wanther flirting show her who's in charge women want a guywhos in charge...