Duke of Misfortune (Dukes of Destiny #4)
Whitney Blake

Unfortunately, Judd is actually Lord Emilian Valencourt, although he's happier when he isn't. His brother is Lord Thomas Valencourt, the Duke of Welburn. There's an ocean of bad blood and secrets between them.
Thomas dies unexpectedly, and Emilian discovers that inheriting a title won't solve his troubles. The late duke ran their family resources into the ground to fuel his vices, so Emilian's best friend suggests looking for a rich woman to marry. Emilian finds the prospect slightly abhorrent, but it's the best of a bad lot of options.
When he meets Miss Theodora Driffield, an opinionated and adventurous heiress chafing under her mother's expectations, his misgivings intensify. She could be the answer to his problems, but he doesn't want to deceive her. Still, compelled by attraction and desperation, the two begin an unconventional courtship—Theodora gives him a black eye after their first kiss; he proposes marriage after they're spotted in a compromising situation.
They fall in love, but Theodora soon determines part of Emilian's subterfuge: she doesn't know that he trod the boards, but she does learn that he needs her money. True to form, she doesn't react placidly. He's utterly petrified when things begin to unravel between them. With everything to lose, he has to summon the nerve to make things right between them and be true to himself.
If he doesn't, Theodora might just slip through his fingers, adding to a lifetime's worth of losses.