On sex in China, see Behind the Red Door: Sex in China, by Richard Burger,Earnshaw Books, Sept 2012. For more info, see here
On love in China and the Chinese moral imagination, see Revolution of the Heart: A Genealogy of Love in China, 1900-1950, by Haiyan Lee, Stanford University Press, 2006 (http://news.stanford.edu/news/2012/february/chinese-love-story-021312.html/). This review includes a beautiful illustration by the poet Wen Yiduo (1899-1946) for a psycho-biographical study of an ill-fated poetess.
Haiyan Lee is currently working on a new book, entitled The Stranger and the Chinese Moral Imagination, a work that focuses on contemporary China and issues of morality as refracted through engagement with strangers. In particular, Lee notes how "socialist China marks certain classes of people as enemies of the state and regards them as strangers, outsiders and pariahs."