He won't do it again because you 'forgave' him. He will do it again because that is who he is. This time was NOT your fault, and when he does it again it will NOT be your fault, and if you stay no matter how many times he does it, how much he agonises and apologises and makes excuses afterwards, and no matter how much he blames your, and deflects, and turns things around in you, and messes with your head, it will still NEVER be your fault.
Never ever ever.
You must, right now, ask yourself. Do you want this? Do you want to spend your time with a man, knowing that he is capable of hitting you, at any time, for any reason or none? Do you want to walk on eggshells, hoping daily that today won't be the day?
Don't want to continue to put up with the other abusive shit that comes with it, because I know that if you're honest with yourself you will know that he was already not treating you right before he hit you. I KNOW this.
I urge you to call up the national domestic abuse helpline today. Go somewhere safe and far from him to do it, because there will likely be a wait, but do not hang up. Talk to them, they will help you to make a plan and leave.
I have been where you are, and I did not have the self esteem to make the right decision. I suffered for years before I realised that it was wrong, and I had done nothing to deserve this treatment, and found the strength to leave.
I left with 4 children, and I've brought them up alone. I am a lioness, and you are too. You just need to believe in yourself. I believe in you. You CAN do this. 

