During the ellipses that mark the break after chapter 10 and before chapter 11, Anna and Vronsky sleep together, although there is no explicit description of the event.
Many of the most important parts of Anna Karenina occur not in words but in silences, as in the critical break in the narrative in which Anna and Vronsky sleep together.
Anna is sobbing, wracked with shame, guilt, and humiliation. Vronsky feels like a murderer contemplating the body he has just murdered. Anna tells Vronsky that she has nothing left but him.
Anna tells herself that she will contemplate her relationship with Vronsky and the mixture of shame, joy, and horror later, when she has more time, but that calm moment never comes.
Anna has a recurring dream in which she is married to both Karenin and Vronsky, and though the situation seems wonderful in the dream, it haunts her like a nightmare when she wakes.
Anna longs to exist peacefully in both her married life and her affair with Vronsky, but she cannot, and she feels guilty about her deeds.