2007, Bitch: Feminist Response to Pop Culture, Issues 34-37, page 363:
One of the first rumored-to-be-asexy relationships can be seen in Henry James's The Bostonians, an 1886 novel that deals with the devotion between two women, Olive and Verena — the work even gave rise to the term "Boston marriages" to describe women who lived together in love with one another without having sex.
Unlike those who choose to abstain by choice — because of, say, religious reasons — the "asexy" claim they have no say in the matter. They're simply not hardwired to want sex.