We'll come right out and say it: there is a whole lot of sex in this book. In the first chapter alone, David has sex with three different women. Still, for all of the hooking up going on, we have to admit that it lacks a certain…steaminess. There is no bosom-heaving, starry-eyed lovemaking in this book. At its best, the sex in Disgrace is physically satisfying, and even then, it usually is only good for one partner. David enjoys himself with the prostitute Soraya, but there's no real connection between the two of them. David thinks he's in love with Melanie – he even considers sex with her to be "making love" (4.1) – but it becomes apparent pretty quickly that the feeling isn't mutual. Bev seems to enjoy doing it with David, but from his perspective he's having sex with her out of pity – he knows it, and he even chastises himself for thinking so.
At its worst, the sex in this novel is pure violation. Even though David's relationship with Melanie seems to be consensual from his perspective, we see her trying to deflect his advances, telling him "not now" to no avail, and ultimately feeling moved to file a complaint against him. It doesn't even really need to be said, but Lucy's rape is the complete antithesis of romantic sex. In this case, sex becomes a violent act of domination of one person (or group of people) over another person, rendering them vulnerable, physically injured, and emotionally scarred.
Coetzee paints a picture of some pretty harsh realities in Disgrace, and so along with that, it seems only fitting that as part of that he shows the many different reasons and ways that people have sex. In doing so, though, we might guess that his choice to leave out the steamy side of doing the deed is a deliberate one. He disrupts the link between sex and love, and instead replaces love with disgrace.