The game works like this. She picks out another man, usually one she has at least a moderate degree of attraction towards, and she flirts with him, either by talking about him in an adoring fashion, or by displaying non-verbal cues of interest to that man while you are around e. She chats him up in your presence, all the while expressing profuse admiration for his most mundane qualities. If online, she exchanges a chain of messages, usually drenched with emoticons.
There's always the chance she is using YOU to get the other guy jealous, by showing him she has guys she hangs out with. Probably was hoping you would flirt with her so he would see she has guys trying to get her all the time. Either way she is playing games and that's not a good indicator of a person you want to get into a relationship with. They love to mess with guys just to get a reaction out of them. I respect the strategy. I don't like games but when someone is toying with your emotions like they are their plaything, it's good to put them in their place. This is very true, I've noticed that girls find more of an accomplishment by getting other girls jealous than guys and getting the guys is just a bonus to solidify that she's somehow better.
To better understand why your girlfriend is trying to make you jealous, you first need to understand that women behave in completely different ways to men. Simple and straight forward. However, women will rarely say or do what they mean. The fact is, a woman will test a man to see how much power she has over him.