Maybe Tomorrow. Enchanted Keepsakes

Two hearts beat as one - two hundred years apart!Tabitha Simpson is on her honeymoon alone, after her fiancé cheated on her. In London she finds a tiny shop, where she buys a miniature portrait. The man in the picture calls to her, as if she already knows him. When she finds the full-size painting, magic happens, and she is transported back in time to 1816. Avery is the Earl of Northcote, expected to marry and provide an heir.
But when he finds Tabby on the sofa of his Thames villa, he is smitten. He doesn't want anybody else. He will defy everybody and everything to have her. But some things can't be defied. Tabby and Avery are madly in love, but they can't stay together. Their lives are two hundred years apart. When Tabby goes home, she knows she can't return. Avery must spend the rest of his life without her, or find a way to join the woman he loves.