[ Sociology ] Open Question : WHYS MY EX BOYFRIEND BEING LIKE THIS?

my ex Jason he's nice one moment tells me he cares about me but then becomes a jerk. talks about other chicks infront of me on purpose, purposly actin like a jerk i think.he still wants to remain friends with me why act so mean? he is so disrespectful as a friend. if he's going to be mean then fuc* i dont want to be his friend. i have a new bf now also.