The memory of all that had happened after her illness: her reconciliation with her husband, its breakdown, the news of Vronsky's wound, his visit, the preparations for divorce, the departure from her husband's house, the parting from her son--all that seemed to her like a delirious dream, from which she had waked up alone with Vronsky abroad.
The thought of the harm caused to her husband aroused in her a feeling like repulsion, and akin to what a drowning man might feel who has shaken off another man clinging to him.
That man did drown.
It was an evil action, of course, but it was the sole means of escape, and better not to brood over these fearful facts.