The first signs of a dangerous abusive relationship cycle is when the victim starts making justifications and/or excuses for the abuser's behavior. "but he didn't mean to", or in your case "he wasn't even aware he did this" Ummm no unless he's a dissociative personality afflicted person and blacks out suddenly - he was aware of hitting you! Don't let him lie and convince you it was any other way. You did something that he let himself get angry about, then he reacted in kind, he hit you. Period. He made a choice and I don't believe for a second his hand "accidentally" caused your arm to turn red. O.o Please step back and see the logic in this before you're caught up in the cycle. It will keep happening if you let it. Get out now.