Platonic relationships in Literature

Eugenie Grandet is the eponymous heroine of Balzac's famous novel. She, the daughter of a rich miser, falls in love with her cousin. He, however, after promising to marry her, leaves & on his return, (in debt), wants to marry someone else for his social advancement. Eugenie pays his debts & sets him free. On the advice of the local clergyman, she marries a local luminary, stipulating however that he not insist on his conjugal rights. He dies after a few years, leaving her a richer widow. Though in her thirties & still handsome, she leads the rest of her life  devoted to philanthropy.

Lucia, in the Mapp & Lucia set of novels by E. F. Benson, is married to "Pepino" & is attended by "Georgie" as knight errant. After Pepino's death, Lucia & Georgie decide to marry for social reasons only, They are still only middle aged but holding contemporary Freud's ideas in abhorrence, decide not to consummate their marriage.

Hoovaiah & Seeta in Kuvempu's "Kanooru Heggadithi", fall in love. But due to elders'  machinations, Seeta is married off to Hoovaiah's younger cousin. But the cousin commits suicide, due to a traumatic event in the family. Hoovaiah is of a spiritual disposition much like Alyosha in Dostoevsky's "The Brothers Karamazov", & has remained unmarried. Though Seeta, now widowed, lives in the same village, their earlier romance moves into a spiritual plane, not needing physical proximity. Both engage in social service in the village.