On Monday, Karenin has a Commission meeting during which he successfully reaches his objectives (which are not elaborated). He's successful in convincing everyone of his point of view on National Minorities; the next day no one talks about anything else. What's even better, he manages to triumph over that rival of his we met at Princess Betsy's croquet party, Stremov.
On Tuesday, Karenin is in his study, completely absorbed in work with his secretary. He forgets that today is the day he told Anna to return home.
He ignores her for a while, even after a servant tells him of her arrival.
Finally, she goes in to see him. He blushes, which is not something he does frequently. He tries to say something, but keeps stopping. In spite of herself, Anna feels sorry for him.
Anna takes the lead in the conversation. She really wants her position to be clarified. She doesn't see how they can go on living as husband and wife under the circumstances.
Karenin's retort is that she doesn't have to perform her wifely obligations (read: sleep with her husband), but that he doesn't ever want to see Vronsky in the house, and that he doesn't want either society or the servants to have just cause to reproach her.