Marriage and sexuality are interconnected, but literary studies do often overlook this connection by attaching a more important value to romantic love and social contract as part of the discussion of marriage in literature. Starting from the end of the nineteenth century the Western society had been increasingly sexualised through the developed fields of science, legal institutions, education and media. Within the twentieth century it became as vital for personal relationships as emotional attachment. That’s why this thesis explores the ways in which sexuality converses with the system of marriage in light of three historical radical periods (1890’s, 1920’s and 1970’s), which contributed to the sexual liberalization. In the context of marriage’s insistence on eternal romantic love, its reservation of a site for economic, social and emotional security, and preference of the model of sexual exclusivity, I analyse the protagonists’ defying behaviours and challenging values, which look for alternatives to marriage-like relationships. Through my detailed analyses of marital and extra-marital relations I put into question the meaning of the illusionary and real in both: recognition of reality goes often versus getting lost in the labyrinths of sexual fantasies and romance. I discuss the social constructions of romantic love, cult of true womanhood and motherhood, gender roles, the system of divorce and liberalization of sex. This thesis demonstrates as well how sexualities are produced through the institution of marriage. This institution can repress certain drives, which are then directed by married people outside marriage, in the places where these drives can be more suitable and easily satisfied. Marriage as the fixed system of regulation of personal relations becomes too outdated in the context of liberalized sexuality within the twentieth century. Thus, sexuality demands changes and new ways of organizing these relations. The novels discussed in this thesis point to various directions where those changes can start.