This woman made a mistake. She was unfaithful without realizing that her husband knew it. But both had made an agreement before their relationship began whoever cheats on the other may be punished in any way. And as she was tied down in part 1 and got all his cum busted in her mouth, she wants to pay back in the same kind—letting him orgasm in her cunt just to make him lick it clean later until she reaches her orgasm. He feels humiliated.