Columbus Short is finally revealing exactly what drove him into such a rage that he delivered a knockout blow to a guy's face earlier this year -- and it might change your opinion of the hot-headed actor.
Short was on Atlanta's V-103 radio station when he was asked about the bar fight back in March, and he said ... "I had to defend my wife at a bar. This man was being highly, highly disrespectful ... slapping her in the face with $20 bills."
TMZ broke the story ... Columbus knocked out Felton Hyche III, and at the time all we knew was that Hyche had allegedly said or done something rude to Short's wife.
Columbus also explains that Hyche was the one who got physical first -- but if what he says about the money to his wife's face is true, we gotta ask ...