Sexual anorexia is a pathological loss of "appetite" for romantic-sexual interaction, often the result of a fear of intimacy to the point that the person has severe anxiety surrounding sexual activity and emotional aspects (i.e. an intimate relationship).
In the view of some practitioners, corroborating the "seminal" work of Patrick Carnes, there are people who appear to have a sexual addiction which is expressed through a variety of behaviors such as the compulsive use of strip clubs, prostitutes, cyberporn sites, etc. but fit the definition of sexual anorexic in that they seem to lack the ability to have a relationship of a sexual nature beyond a paid-for or anonymous experience. The person does not have an aversion to sex but to intimacy.