How to confront my friend about being 'too friendly' with my boyfriend without sounding like the evil gf?

My boyfriend is a bit clueless and I think he's worth it to go through all this drama. My mother told me I should confront my boyfriend in a friendly matter about respecting my wishes. I know my boyfriend would understand and never talk to her again...luckly for me this probelm just begun which is good because my boyfriend knows she is being very flirty and finds it weird but still being a typical guy and going along with it. My boyfriend is nuts about me and I trust him but I want to confront her so she would know she is being too flirty and to respect my wishes. How should I confront her about the public flirting with my boyfriend? Another thing is I live in new jersey and my boyfriend moved to new york but we still see each other on weekends luckly we don't have to see her at all. I know I shouldn't be jealous cause people tell me not to worry but again beauty is in the eye of the beholder...so maybe he might like her personality. When you have amazing boyfriend, you will always be kind of scared to lose him...we always liked each other. I have my reasons to be worried cause this girl is telling my boyfriend she loves him and he's the best but he doesn't say one thing about me on facebook. Anways how to confront them both with out sounding like the jealous girl friend? What should I say to him about his? Because she has a big history of stealing people bfs..