Sea Bride by Mollie Donoghue

Heiress and orphan Rebecca Daughtry yearns for more but suspects her life is destined for boredom and decorum thanks to a decade-long engagement to the rigid Alexander Paine, a much sought after gentleman and landowner who grew up across the ocean. Now a passionate young woman of 19, she's ready to face her future as Paine's Bride in a sweltering and faraway land.
The exhausting and unsettling journey to her new life is disrupted by a disaster at sea, a deep betrayal and the unwelcome discovery her fiancé has been presumed dead for some years. To survive and make her way to freedom, Rebecca must build an alliance with The Duke, a disgraced nobleman turned vigilante pirate who wishes to see Rebecca make it out of the West Indies alive as much as he wants to chase down their common enemy.