If you don't remember, they're arguing in bed because she won't f*** him and he says something to the effect of "go back to Jack!! You'll just find some new reason to get pissed off at him a week from now and bounce riiiight back!" Then she slaps him.
Since that was such a great line (because it's meta) I'm one hundred percent on Sawyer's side!!!
I guess I'll have to watch Justified since you've recommended it to me 1,084 times now.
NP: Pearl Jam - "In My Tree"