Machiko

History
While it is proven that she had an affair, her true intentions towards telling her husband that the child was not his are not certain.

In the first episode, the viewer is made to think that she was lying about loving Takashi at all, and was only marrying him for money and status.

However, in the second episode we see a different side of the story. The Black-Haired Woman says that Machiko probably greatly regretted her affair, and that it could have possibly been a one-time event, which is the opposite of what the first episode leads the viewer to believe. The Black-Haired Woman also says that she believes the child Machiko was carrying was indeed Takashi's, but upon seeing Takashi break down at the loss of his child, lied to him and told him that the child was not his, to lighten his burden in his final moments if only a little.