The Duke of Diamonds by V. C. Lluxe

A highwayman duke is a contradiction in terms. There’s no reason for a wealthy and titled man to turn to violent armed robbery. And yet, the Lady Balley, Patience Needbrooke, is positive she recognizes the tall, dark man who pulls her from her carriage that night.
“I. Am. Kidnapping. You,” he tells her, speaking quite slowly and enunciating as if she’s an idiot.
Patience isn’t sure which is worse—being kidnapped by some mad duke or being returned to the man who the duke will appeal to for ransom. Her husband regularly beats her. It’s a bad world, or so it seems to her, and she must bear it up and make what she can of it.