I'm not sure this'll be your thing at all, but it's one of the only romance novels I've ever read. Well, it's a romance inside historical novel... or the other way around. The book is Désirée by Annemarie Selinko, and here's a bit of a review from amazon:

In his memoirs, dictated while he was in exile on the island of St. Helena, Napoleon named his first love as Desiree Clary, a silk merchant's daughter from Marseilles. In the breathtaking novel simply titled Desiree, author Annemarie Selinko chronicles the life of the woman who was Napoleon's fiancee, a woman who rose from being a commoner to becoming a wife of a General to Queen of Sweden and Norway.

It's just a wonderful story, and one I've loved for years. And I mean years, I was probably only 12 or 13 when I read it for the first time.