Celie talks to Sofia, who is fixing the roof of her and Harpo's shack. Sofia tells Celie that she no longer has any sexual interest in Harpo, who seems obsessed with making her obey him, and with growing larger, by eating enormous amounts of food, in order to seem more physically imposing. Sofia considers taking the children and going to stay with her sister Odessa for a while.
This scene is indicative of Sofia's abilities around the house—not only can she take care of the children, but she can also physically keep the house in good condition. It is implied that Harpo is not particularly skilled at this kind of labor, although Harpo does help Swain build the bar later in the novel.
This conversation causes Celie to think about her own marriage. Celie thinks about her lovemaking with Mr. ____; he cares only about his own pleasure, and Celie dreams about Shug when they're having sex. Sofia complains, to Celie, that Harpo too thinks only of himself when the two of them are having sex. She tells Celie she wants a "vacation" from her marriage, since she no longer desires Harpo physically, and finds his bossiness and attempts at abuse frustrating.
Mr. ____'s lovemaking with Celie really does not involve Celie as a person. But because of Celie's past, she does not understand that a woman might also take pleasure from sex. And if she does understand this—as she seems to glean from Shug's interactions with Mr. ____—she believes this kind of pleasure is not possible for her.