You haven't done anything to make him dislike you. He is convincing himself to dislike you because that is the only way he can justify his actions to himself. How could he live with himself if he admitted you hadn't done anything wrong? At this stage he can't deal with it.
If it's any consolation most breakups start off this way and the communication gradually improves again once the initial shock and misery wears off. People adjust to their new arrangements and patterns are established, and the need for difficult and painful conversations dissipates. As the period of grief begins to fizzle out, a new relationship will form between you and h where you no longer see each other as the enemy. You will reach a kind of truce where it may even be pleasant to see him once a week and have a cup of tea together while you discuss your sons. He will (hopefully) become a friend.
I know this all sounds ridiculous to you now because just the sight of him is still so painful to you. But I PROMISE it will happen one day. You may grow to like him as a friend, or you may find you can never like him again, but either way you will get used to seeing him without feeling all this intensity, and life will settle down.
Just ride the storm, as ever. It will come to an end one of these days, and you will look forward to the rest of your life with excitement again.