The Presumptuous Earl

This is a steamy historical romance short story (word count 5, 254). Claire is under no illusion that Anthony the Earl of Beaumont has no great liking of her, but merely tolerates her as one of his sister's closet friends. But Claire is soon to become completely confused. If the Earl thinks she has such a bad character why is he instigating passionate encounters between them and requesting that she officially becomes his mistress?!Even more shocking, why is she responding so wantonly in turn to his advances, allowing him to give and take pleasure from her so freely?!