You know the song and dance...
Partner one says, "I'm upset about this thing that happened." Partner two says, "I didn't do anything wrong!" Partner one says, "You did xyz!" Partner two says, "That's only because you did abc!" And then the two careen into a fight that has no real beginning and no real end.
Both partners feel justified. Both partners feel vilified. Both partners leave feeling misunderstood, ignored, and frustrated.