Henry James coined the term “Boston marriage” in his 1886 novel, “The Bostonians” which involves a long term cohabiting relationship between two unmarried women. Alice, Henry James’ sister, lived with another women and was one of his inspirations for the novel.
19th century society saw nothing unusual about two unmarried women living together, the very idea of two women having sex with each other was incomprehensible at that time. Women were thought to lack sexual desire and so a close bond between two women was seen as “sisterly” and purely innocent.
Thanks, Jeffrey Gent