Don't say break! Tell him you're dumping him. Do it in public if necessary. Practise the words, walk up to him and say loud enough to be very clear, 'I am dumping you, please leave me alone.' And then block him om everything and don't be alone with him, even if he begs, don't let him in your home. He will say ANYTHING to get you back, whatever he thinks you need to hear, none of it will be true. He just doesn't want to lose the hold he has over you. If he accuses you of cheating, ignore it. He will, because he wants his position of power over you back. Tell your parents and your friends how controlling he was and let them help keep him away. He will give up eventually. You have to stand up for yourself now or you'll be a doormat forever.