Relationship problems please help?

I am a freshman in college and I need help. In November I began hanging out with this guy a lot. He is a sopre and in a fraternity and is really awesome. He has become one of my closest friends. There is only one problem, he has a girlfriend. They have only been dating for a month but it still he has one. Everyone believes that we are dating even though we aren't. He spends more time with me then he does with his girlfriend. We text at least a couple hundred times a day. We are both naturally friendly people so we do things like holding hands. He also tells me things that he doesn't tell his girlfriend. One of my friends said I am having an emotional affair with him, is this true? If so what should I do? Please help.