Girlfriend wants me to tell my "girl-friend" to get the hell away. Is she right? Should I listen to her?

I think your girlfriend is right when she says she doesn't want you to talk to this girl. You obviously have some emotional attachment to her that is far from platonic, just as she does for you. Secondly, she's disrespecting your girlfriend. Why would you want to be her friend anyway? Friends don't do that. I also don't understand why you can't show your affection for your girlfriend around her. Because she likes you? So what?! See... you have a problem. Stop talking to this chick because you obviously have a little crush on her. I wouldn't even bother dating you. Your girlfriend is an idiot for staying with someone who cares more about the emotions of some other woman has for him than his own relationship.