Dude, if she is pissed at you your hosed! Hitting a woman is wrong in my book unless she could take ya herself. I'm on the fence on that as some of them start shit and the man still looses...
Back to your story. If she decides to say you slapped her around, she could go to her girl friends, have them slap her up, or she does it herself, and then calls to say you beat her.
Your wrong all ways around. Ditch everything illegal and wait for the knock on the door. I went through an ugly divorce where the bitch pulled the fake beating thing because kids were involved.
You sir, when it comes to doing wrong to a woman, are guilty until proven innocent.
In my state, if the cops sees a mark on male or female, and they think there was a fight (people living together), they MUST arrest someone. If they are wrong, they are protected by law from being sued.