Serpukhovskoy's offer and warning

Vronsky's advantage is a code that settles everything inside a small circle: the card-sharper must be paid and the tailor need not; one may not lie to a man but may to a woman; one must deceive nobody except a husband; an insult must never be forgiven and may be given. Within it his position is clear — Anna is worthy of more respect than a wife, Society may suspect but must not speak, and the husband is a superfluous hindrance whose only right is to demand satisfaction, which Vronsky has always been ready to give. The pregnancy falls outside the code. His heart proposed that she leave her husband; on reflection he sees he would have to find money and leave the army, which raises the secret question of ambition. Serpukhovskoy, his rival from the Cadet Corps, is back from Central Asia a General and a rising star, while Vronsky is still a Cavalry Captain playing the independent man. He concludes that he loses nothing by staying, that she does not want her position changed, and goes out clear and calm.

The code is set out as a list so the reader can see exactly where it runs out — at a pregnancy — and Tolstoy has Vronsky reason his way back from the offer his heart made a day earlier. Ambition is named as the passion he never admits, and Serpukhovskoy's promotion does more to keep Anna in her marriage than anything Karenin writes.