OK I’ve run into this sort of situation a couple of times and there is a third alternative. Granted I happened across it by accident and only after doing the two wrong ways on several occasions.
Option one as stated is to be confrontational, wrong…it shows jealousy and weakness, Gentleman is right on about that.
Option two, do nothing…again wrong as it shows timidity.
Option three however, I had my back to a situation once where a guy was trying to game the girl I was with. Being totally oblivious I turned my head half way to her general direction and called her over. She excused herself from the conversation and came. I didn’t block him, I gave her the opportunity to basically reject him herself and do so in a way that leaves him thinking of me as the one with dominance in the relationship.
Now I don’t recommend snapping your fingers or being overly arrogant about how you do it. You don’t want to call her over in a way that makes her feel like she looks like a slave or anything like that. Simply call her over in a very casual and matter of fact way.
“Hey babe could you come her for a sec, I want you to meet a friend of mine.”
Or “Hey hon, we’re about to go, come on.”
then if she does reward what is basically a light compliance test with some affection by giving her a kiss that makes her feel good about coming over and publicly displays that she answered a BOYFRIENDS call and not just one of her guy friends.
This seems to spare the chest thumping of direct confrontation and the coward appearance of no confrontation and does so in a way that establishes a value ladder.
He displays value that is low in relation to her by being obvious about trying to game her.
You display high value by staying put and expecting (not demanding) that she come to you.
By responding favorably to your call she establishes a value comparison between you and the other guy where her own actions convince her that he’s not worth her time.