Also try setting the ground rules. Can your girlfriend go for a movie (like TwilightJ) with her male friend? Does she mind you going to nightclubs with your female colleague? Work to create rules that are mutually agreeable. Work hard to stick to them but keep in mind that amending the rules may be necessary down the line.
Random scenarios:
1) She was right. NCell mobile service provider might be having technical issues.
2) She was talking with her female friends about going for a movie with some nice guys*. But she doesn’t want to mention it fearing that you might go insane with jealousy. In short, she doesn’t want to lose you. Btw, you don’t have to be insecure about nice guys. They never get laid. J
* Nice guy
1) The person every girl will compare their would-be boyfriends to, for they possess every trait a woman desires. However, for whatever reason, women avoid them like the plague.