Should I be Hanging Out with my EX GF ? After What Happend Between us...?

Ok, we started dating last january, n we broke it off for good in June. We had many fights, she used to lie to me, hook up with other guys if we had fights, do things to make me mad, it was games with her. I really loved her, (not anymore), so when we broke up, I really had it rough on me, problems with parents, work, people, friends, I was hearth broken. One day I decided to move to another state, Vegas because we had the same friends, she used to hang out with most of em, n I just couldnt take it anymore. I left, Two months after we were done for good, n I came back accouple times, we saw each other, everything was fine. She had many bf's after we broke up :) but she was just game with them 2 I guess. Now she moved with her family to Vegas, n I was in Europe till now, and now Im going back there to Vegas. My Questions are: Should I hang out with her if we somehow c each other, or she calls me to hang out? Should I just ignore her, n tell her I dnt have time? Or how should I act? TY