Personally I would talk to your girlfriend about your feelings for the guy first. It hurts when you like a guy and then your girlfriend goes out with him without letting you know. I lost a friendship by doing this very thing in a state of drunkeness. I miss my friend to this day and that was some 18 years ago. She has forgiven me but our intimate friendship was lost and we no longer share with each other. I see her once every couple of years. I believe if I hadn't done what I did and just told her how I felt for this guy that things would have worked out. He really wasn't her type and she would have tired of him quickly. I ended up marrying him but if I had been able to show my friend the respect she deserved I would still have her as well as my husband.
Zen

<font color=blue>I was always looking outside myself for strength and confidence but, it comes from within. It is there all the time.--Anna Freud