The Last of the Barons, Book VI by Edward Bulwer-lytton

For several days Hastings avoided Sibyll; in truth, he felt remorse for his design, and in his various, active, and brilliant life he had not the leisure for obstinate and systematic siege to a single virtue, nor was he, perhaps, any longer capable of deep and enduring passion; his heart, like that of many a chevalier in the earlier day, had lavished itself upon one object, and sullenly, upon regrets and dreams, and vain anger and idle scorn, it had exhausted those sentiments which make the sum of true love. And so, like Petrarch, whom his taste and fancy worshipped, and many another votary of the gentil Dieu, while his imagination devoted itself to the chaste and distant ideal -- the spiritual Laura -- his senses, ever vagrant and disengaged, settled without scruple upon the thousand Cynthias of the minute. But then those Cynthias were, for the most part, and especially of late years, easy and light-won nymphs; their coyest were of another clay from the tender but lofty Sibyll.

And Hastings shrunk from the cold-blooded and deliberate seduction of one so pure, while he could not reconcile his mind to contemplate marriage with a girl who could give nothing to his ambition; and yet it was not in this last reluctance only his ambition that startled and recoiled. In that strange tyranny over his whole soul which Katherine Bonville secretly exercised, he did not dare to place a new barrier evermore between her and himself. The Lord Bonville was of infirm health; he had been more than once near to death's door; and Hastings, in every succeeding fancy that beguiled his path, recalled the thrill of his heart when it had whispered "Katherine, the loved of thy youth, may yet be thine!"