I love this girl but she has a bf what shuld i do?

k ive loved this girl for a yr now ever since i came to the skool ive had feelings for her and she knows how i feel about her andshe says she loves me but then she sayd she loved this otehr guy shes goin out wit and she says she isnt sure who she loved more ive wnt out wit her once b4 wen theyy broke up and we went out fro a 3 months then i hav no clue wut happened but then it was suddenly over and a few weeks later she started goin otu wit thsi guy again....and i hate the guy and he hates me and at my friends party... well her bf wasnt there and she kissed me then ... we started... makin out.. and like everyone at the party saw and no1 told him and im nto sure wut to do i love her so mucha and she says she loved me wut shuld i do?