Never kick a man in the nuts?
You've obviously never been in a real fight with real consequences. You do WHATEVER you have to. Rules/ethics have no place when a situation goes to blows.
To the OP...I don't care what the circumstances are...how do you allow someone to put their hands on your girl? And, it wasn't a cheapshot, you're just naive. If he was willing to push your chick, you think he's not going to swing on you? Really? AND, you looked away? He didn't cheapshot you, he made the decision that shit was going down, and you didn't respond. If he wasn't looking for shit to escalate to that level, he wouldn't have followed after you. Lesson learned, and it's been said already, if you're not really in a position to get away quickly/remove yourself from the situation, throw your fucking hands or don't be surprised when you're the dude lumped up fighting with EMTs.
Having fun at skiing's expense since '09.