The Dark Angel by Kathryn Le Veque

It’s not often the House of de Velt sees both tragedy and comedy, but when Medieval hippies come to call on the darkest lord of all, Julian de Velt gets caught up in the Medieval mayhem…
But he pays a price.
Lista de la Mere is a young woman of beauty, sense, and education. Unfortunately, her mother and her aunt don’t have the same sensibilities. Lista is an heiress, and a very wealthy one, and if her conniving, alcoholic mother and her sly, drug-addicted aunt have anything to say about it, she’s going to marry the man that can provide them with unlimited coinage to feed their habits – and put them back on top of the social hierarchy.
Lista’s mother was a friend of Kellington Coleby de Velt, Julian’s mother, long ago. They pitch Lista to Kellington as a wife for Julian and although Julian has no intention of marrying any time soon, he’s rather intrigued with the lovely, bright young woman who is so capable of drawing him out of his shell.
But Lista’s mother and aunt don’t stop there. It’s their intention to have a bidding war, the prize being Lista, and they pitch Lista to another knight, a man who is friendly until he feels Julian has wronged him. Julian, who is usually shy and quiet, must call forth the inner devil that his father managed to tame so ably to protect what is his.