The nasty, filthy bastard cheated on his girlfriend. If there is something that Mistress Gitta really hates, then this is it. You can clearly see that when he confesses his sin, Gittas expression darkens and her voice becomes really tensed. So, in one way, he is lucky that he admitted his deed because it seems that he is braver than he seems but on the other hand, he created a storm that can clearly blow him away. So the rest of the punishment goes on in the spirit of his betrayal and he gets as many verbal hits as physical.