When you're in a relationship, it is perfectly normal to worry that your girlfriend and her guy friends are getting a little too close. Short of slapping a GPS system on her car, how do you know when it is okay to get jealous and possibly kick some ass?

The Childhood Friend
This guy has been around forever and she will not be willing to give him up. While their nicknames and constant phone conversations might annoy the hell out of you, you will have to grin and bear it on this one. Being jealous of the best friend will only drive your girl away. Ask him to hang out for a guy's night so that you can feel him out better.

The Ex
Unfortunately, a lot of girls stay friends with their exes, which can make you more than uncomfortable. Even when people say they had a mutual breakup, usually someone still carries a torch. This is definitely a friend you should be wary of because even if he is not still in love with her, he might just want to see if he can get her back from you. If they are going to have lunch--be open minded, if they are going to have drinks--start worrying.

The Co-Worker
This situation can be sticky. Since you aren't there to see how friendly things get, you need to listen closely when she talks about work. Things are good if he has a significant other, but that does not guarantee anything. If she mentions him all the time, talks to him outside of work, and takes many lunches with only him, it is time to start showing up at the office for her lunch hour.

The "New" Friend
This needs little explanation. What guy wants to be just friends with your woman? Unless he is engaged or married, this friend only wants one thing.

The Gays
She spends just as much time with her gay friend as most girls spend with their girl friends. While he has an in on everything your girl thinks, he usually does not want to be too far in with her. Unless she laughingly tells you he kissed her or told her he loves her, this is one threat you don't have to worry about.