Listen, there is only one way to beat him at this game and that is for you not to grow hard from this experience. Growing hard will only prevent you from meeting the right person and moving on with your life. I know it is easier said then done, but for your own sake, find a way to put distance between you and this miss adventure and trust that not all men are deceitful. You're in a much better position then this other girl who is wasting her time on someone with such low integrity. But seriously, really try to find some survival techniques so that you don't grow bitter and that you can open yourself up to the right person. Best of luck.