HE IS SUCH A BLEEP!!!! HELP!?

my ex boyfriend broke up with me 4 months ago for another chick that he only kenw for 5 months while we dated for a year and a half. Before they started dating she would flirt with him and say she loves him. But behind her back he'd talk crap about her saying she was fat and ugly and a lot of other things but to her face he was a kiss ***. Now he dumped me for her and 4 months later a see a picture of them kissing on facebook. my heart is broken all over again ): why would he talk crap about her and ME? Break up with me for her if he thought she was so ugly? Wth is his problem??