He's your rival on the set, and any work you do together results in a lot of stress and arguments. So why did he offer to co-star in a movie right after you were announced as the lead? And why does he keep telling the screenwriter to change the script so that the adult content scenes are more "realistic"?

You hate each other because you are both extremely stubborn and you haven't gotten along since the day you met at a lead audition.

I don't know if there is a trigger, maybe it's manipulation. Sorry