It's interesting that this site that CeMar mentioned called "The Marriage Bed," a site that deals with sexuality for Christians has a section in the Message Boards called "Sexual Sin," and under that topic are four subtopics: Pornography, Infidelity, Lust & Immodesty and Sexual Refusal (my spouse won't have sex). Interesting that they put Sexual Refusal in a category with those other "sins." (I didn't go into the topics because I didn't want to register on the site.)