Have most people on this thread really never done something completely out character?
I've been with my dh for 15 years, through stresses, illnesses, children, bereavements, money problems . . . If my relationship was to become an abusive one it would most likely have done so by now.
Still though a few years ago we had a horrendous row! I had a bottle in my hand which he thought i was going to smash his head in with and he was holding a knife! (he was loading the dishwasher!) To anyone watching it would have looked awful, especially when i walked out of the house and he followed me. I locked myself in the car and he was trying to get in (both knife and bottle had been abandoned by this time). Imagine how that would have looked to the neighbours. I drove away with him telling me never to come back.
I got a few minutes down the road and he called and asked me to come home. When i got there we looked at each other with shock and bewilderment. It was the strangest thing. We have a really good relationship but had some stuff going on in our lives at the time that was making us both tense.
The row came out of nowhere and lasted seconds. Neither of us even knew what it was about!
It was horrendous and shocking and we both acted out of character, probably him more than me.
I do believe its possible for someone to act horrendously as a one off. Only the op knows what he is really like. If he is the type to become abusive then there will undoubtedly be red flags.
Instead of just telling her to leave him, how about someone post a link or info on the red flags and the op can read it whilst being completely honest with herself about this man (if she wants to and ready).