The Future with the Marquess by Brooke Losee

Miss Katherine Garrick has completely stolen Nicholas Betham’s heart. Due to her mother’s disdain and his reputation as a rake, a title imposed upon him by the ton, obtaining permission for courtship has proven impossible. When the banns announce her engagement to another man, Nicholas is determined to let her go. His foolish heart, however, is not so easily convinced.
Having accepted a proposal from a man of title, Katherine Garrick has secured a life of comfort and prestige.The success means little, though, when she longs for acceptance and a world where women may study whatever they wish. With her freedom dwindling, she has one last chance to experience a future she should know nothing about.
Desperate to escape the expectations of her mother and Society, Katherine searches for a set of time traveling pearls. They send her and an unsuspecting Nicholas two hundred years into the future, but with a secret organization hunting the cursed heirloom, danger lurks in every era, and Katherine and Nicholas discover their futures may lie with each other, only if they survive.