Mary Robinette Kowal 
Glamour in Glass [EPUB ebook] 

Jane and David Vincent, both glamourists of some repute, are enjoying a blissful honeymoon on the continent when their romantic getaway goes horribly awry. They are in Belgium when they learn that Napoleon Bonaparte, the deposed emperor, has fled from exile throwing Europe into turmoil. Suddenly Jane and David find themselves in great danger, with no easy way back home to England, no possibility of rescue from abroad, and no real way to tell friend from foe. When David is taken prisoner, Jane determines to put herself at risk, using her most cunning, strongest magic to save her beloved, herself, and their unborn child from harm. . .