Mr. ____ and Grady spend the Christmas holiday drinking, and Shug and Celie catch up and talk. Shug has become incredibly successful, singing all over the country—she has purchased cars and a house in Memphis. She met Grady, who is a mechanic, while he was working on her car at a gas station, and married him quickly thereafter.
Again, Shug's career has really taken off—she sings everywhere, and is beginning to develop a name for herself. But Celie does not care about Shug's fame; she only cares that Shug is living the life she wants to lead.
Shug asks whether Mr. ____ still beats Celie. Celie replies that Mr. ____ is kinder to her, in general, though he still beats her sometimes. Their sex has also improved, with Mr. ____ trying more concertedly to increase Celie's pleasure. But Celie still claims she's a "virgin" as far as her own pleasure is concerned—implying, to Shug, that she has not had an orgasm with Mr. ____.
Celie is not lying here; it does appear that, since Shug left, Mr. ____ has been nicer to Celie. But Celie still craves the kind of independence that Shug has—the ability to go where she wants, when she wants, the ability the determine the course of her own life. Further, she wants to experience the kind of pleasure that Shug experiences, and she can only do that with Shug.