The both of you have been on a wild ride and during the holidays, people get sentimental so they do stupid things they wouldn't normally do. He's stupid for showing up and thinking that he can re-write history. Don't trust him, don't change your life around, and don't let him cross your boundries. Stand your ground. After the holidays are over, life will return to it's mundane norm and suddenly, everyone will look the same as they did in the past. Stand strong.