Shes not the one. You wont be able to trust her again. And trust is very important in a relationship. You should move on. Yes its hard. Talk to friends. Cut out contact with this girl. Cry it out. distract yourself. Have a close friend you can cry to. Each time you have the urge to call her, call a friend to stop you. Cry to your friend but dont call her. Move on. And may be start seeing someone else!