Her honour for an heir

Three years after her wedding day, Vanessa remains a virgin. Her sickly, cruel husband, the Duke of Tarrick demands she produces an heir with a man of his choosing.
Vanessa’s choices are narrowing every day. To refuse leaves her penniless and alone for when the cruel Duke dies his estate passes elsewhere.
To submit would see her honor surrendered to the new stablehand Fitz. His sparkling green eyes might match her husband, but his cocky, arrogant attitude riles her. He sees no value in her titles and riches, seeking only to enjoy life’s opportunities. Including sleeping with a famously beautiful Duchess.
The added risk of snooping on servants and family scandal suggests Vanessa should stick to her husband's strict rules and simply endure what has been arranged.
But what if giving away her honor to such a casual rogue is the spark that makes her bland world finally explode into life?