girl flirts with me but has a boyfriend. what should I do ?

I have a classmate in college. She is really pretty,intelligent, and funny. But she has a boyfriend. We have hung out alone on several occasions. No funny business has gone on except for the occasional tickle fight (which happened while watching a movie in my bed) and constant sarcastic humor. We have recently started telling each other some of our deepest secrets. She looks at me and acts like she is interested in me. Before we hung out she had told people in the class how she was getting married to this guy in the future and that he was her everything. When we hang out she rarely mentions him and when she does its usually saying something about how he isn't as sucessful or out going as me or as she would like him to be. Is it possible she is interested in me ? Or am I just naive ? Plus I don't want to be a home wrecker but I am really really into this girl.