That sounds like a long and protracted controlling and violent incident, not the first, and no, I have never ever met a woman who says "He only hit me once, it was 5 years ago and he never did again"
That's because it happens so rarely, if at all, for it to be statistically insignificant.
What does happen is that the woman will stay with him and the line has moved. that line - his personal line - has gone beyond hitting the mother of his child in front of the child. he has done it and there have been no consequences - ergo he will probably do it again, next time you make him angry.
This time he grabbed you round the throat - what about next time/ next time, he might black your eye - and that will be a one off too.
After that it could be a sullen kick with a steel toe capped boot to your knee cap - so easily done, so easy to say he was aiming for the wall and missed - but will probably still hurt 3 years later.
Things might go quiet for a year or too. You might decide to have another baby with him - and suddenly, you're pregnant, you feel like crap, you can't manage to do the huge amount of running around and placating that living with a violent and volatile (as a one off, of course) man requires. He resents your pregnancy, he resents your eldest child, you are both standing there and in that instant, who does he hate the most? Who is he angry with the most? The wife he perceives as lazy? The child he perceives as naughty?
Who will get the blow?
In 12 years time, you are going to have at least one teenager - not the most empathic, emotionally sensitive and naturally passive creatures.
How many one offs will she get?