It appears whatever he has done he's done before or at least something similar. By taking him back you have become an "enabler!" DON'T TAKE HIM BACK! Give yourself a chance to meet new guys and have a little fun, and if your ex is worth it he'll smarten up and fight to get you back (not physically) but to show you he really has changed. Don't be a statistic and buy the fact he's changed because it takes time to change problems in your own personality and can't be done over-night.