From my POV, it’s actually got little to do with the fact that they’re women. Big men shouldn’t beat on little men. Teens shouldn’t beat on boys. Boys shouldn’t beat on babies.  Strength is for physical protection and defense, not for preserving pride.  The right thing for this guy to do wasn’t to wallop her, nor was it for him to stay and get hit. He was supposed to leave.  Anybody who thinks this guy was in the right is a loser who misunderstands the principles of humility and civility. A man doesn’t assert his strength just because he can’t handle the difficult emotions of a situation. A man withstands everything he possibly can, and avoids violence at all costs.