You guys were forced to be with each other because of your parents. Yet he still loves his ex that he was forced to break up with because of your forced relationship with him. So ever since, he was distant and cold toward you, fully making you aware that he didn't like you at all.

"I told you many times! I don't love you! I love Ella! Can't you God damn understand that you're just someone I hate!?" He said, his voice was full of madness.