19 reasons.

He's a jerk because he made something of beauty to ashes.
He's a jerk because he let didn't pick you up when you fell.
He's a jerk because he didn't say he loved you as much as he felt.
He's a jerk because he don't have the guts to take the initiative.
He's a jerk because he put other things above you.
He's a jerk because he thinks too much.
He's a jerk because he isn't worthy enough for you.
He's a jerk because he doesn't give in much to you.
He's a jerk because he left a hole in you.
He's a jerk because he has a lot of pride.
He's a jerk because he didn't appreciate you as much.
He's a jerk because he didn't cherish you as of now.
He's a jerk because he is a selfish person.
He's a jerk because he's cooking sucked.
He's a jerk because he didn't gave you enough security.
He's a jerk because he's full of shit.
He's a jerk because he hurt you time and time again.
He's a jerk because he gave you an incomplete gift.
He's a jerk because he's full of empty promises.