It depends on the situation. If I was with my fiance probably not unless it escalated to that point and someone was putting their hands on her but I would typically just get her out of harms way, show the other guy that I am not backing down from telling him what he is doing wrong. Obviously, in a bar / club though and dealing with drunk assholes it can escelate quick and for no reason what so ever. If it was just words being said that was disrespectful then it can be handled without violence every time. They are just words afterall. I was in a situation once where I was entering a bar with some friends and out of nowhere a drunk guy on his way out just sucker punched my friend and before my friend even knew what was going on I had hit the guy twice and put him on the ground where security can grab him and take him outside. In those situations it's just an instinctual protection mode of loved ones and not a lot of pre meditated thought goes into it before all hell breaks loose. We all learn from situations like that and just try to avoid it in the future by being more aware of our surroundings. Again, I am not claiming to be a badass or anything and to be honest it wasn't taht difficult taking care of a drunk guy but the dude initiated everything unwarranted and attacked my friend so he still got what he deserved regardless of how drunk he was. He probably doesn't even remember that night so I guess he wins.

I can tell regardless of the "situation" if you assault someone over words, and they didn't touch you or your fiancé, you absolutely deserve to be put in jail and sued, and you are wrong. A mature adult should be able to ignore or walk away from verbal nonsense.