By the time Hardy wrote Tess of the D'Urbervilles, he was a successful novelist with an established reputation. Earlier in his career, under the advice of such mentors as Leslie Stephen, Virginia Woolf's father, he moderated his criticism of repressive Victorian social restrictions and Victorian hypocrisy. By the 1890s, however, he was secure enough as a literary figure to write a novel that expressed his true feelings about the double sexual standards applied to men and women in his society. It bothered him that men got a pass in his culture for being sexually promiscuous, while a woman who "strayed" in the slightest way, even if it was not her fault, was severely condemned and often had her life ruined.
Hardy portrays the injustice of what happens to the innocent and pure-hearted Tess, whose life is ripped apart because she is raped and impregnated by a predatory man when she is only a teenager. Even after she "buries" her past by moving to the dairy and starting over, her past still dogs her. When she is honest and good-hearted enough to confess her past to her new husband, Angel Clare, who has just confessed his sexual misdeeds, Angel turns against her. He applies a double sexual standard in which it is perfectly reasonable for he, a male, to be sexually experienced but an unpardonable sin for Tess, a woman, to be in the same situation. He leaves her and goes to Brazil because he can't handle that she is not a virgin, even though he is not a virgin.
The book was criticized at the time for asserting Tess was a "pure woman." Today we can more easily see Tess as the victim she was of a cruel social system which held women to almost impossibly high sexual standards.