Although I've been a fan of Ms. James for several years, This Duchess of Mine will become one of my favorite books by this author.  She jumps away from the formula for a romance in just enough fashion it drew me in.  The hero is dying, the heroine is desperate to save him, and together they fight demons from the past and present to resolve this inner and outer conflict.   It is not until almost the end of the book that readers are allowed to see what does happen to the Duke, who is by far one of the most heroic heroes I've ever had the pleasure of reading.  His Duchess also is a character who will live on in my memory as a woman who will do anything to save the man she loves.

Jemma is not at all pleased to be summoned back to England just to have Elijah, The Duke of Beaumont, refuse to share her bed.  After all, it was his idea to sire an heir.  Just because he is still miffed that she did what he asked her to do while in France—take a lover—after he cheated on her in their first months of marriage, doesn't mean he has the right to dictate if they do or do not make love.  For Jemma is in love with the Duke. He stole her heart at a young age and less than a decade later she still loves him beyond distraction.   But something is not right with Elijah, he is too secretive.

Elijah hates that he hurt Jemma. His reason for taking a mistress was to put pay to rumors he was like his father, a man out to sleep with any woman and sometimes two or three at the same time.  Although he kept a mistress, he hated doing so.  He has always loved Jemma, and he believes she loves him, only now he is dying and there is nothing he or she can do to stop his failing heart.  His talks with his sensual duchess about what to do when he dies are met with disbelief, horror, and an unswayable determination to find a cure for what ails Elijah. Before they can move forward, both the Duke and Duchess must put to rest past mistakes and plot a course that will steer them toward Elijah's good health before it is too late.