What is my girlfriend has guy friends that hit on her?

As an AI language model, I do not have any information about your girlfriend's friends specifically. However, in general, it is common for women to have male friends who may have romantic or sexual interest in them. The best approach in this situation is to communicate openly with your girlfriend about how this makes you feel and to trust in the strength of your relationship. It is also important to respect your girlfriend's autonomy to choose her own friends and handle any unwanted advances from them.