Lord Darkness by Sydney Jane Baily

A marquess on the verge of greatness is devastated by tragedy… and only she can restore the man he used to be.
Lord Christopher Westing, heir to a dukedom, is a magnificent marquess at the pinnacle of London society, darling of the ton. He is a veritable god to the women who pursue him, and furthermore, his future holds a prominent place in Parliament. Life grows even grander when he realizes the only woman for him has been right there all along.
But his world is upended in a single devastating moment. When he is on the cusp of a once once-in-a-lifetime love, his world comes crashing down. When an unimaginable accident causes Christopher to plunge into a terrifying world of darkness, both his sunny disposition and his will to live disappear as swiftly as the light in his eyes.
The esteemed but reticent Lady Jane Chatley has admired the marquess for years, though he’s never shown her a twinge of romantic interest. But in one extraordinary night, everything changes. A kiss like nothing she—or he—has ever imagined makes her irrevocably his. But with the marquess pushing everyone away, can the ever-capable Jane keep him from slipping into bleak hopelessness? Can she make him believe in what he can no longer see—before it is too late for both of them?