The Female Husband
This was once a thing. Women who lived as men and “married” other women. As far as I know, it’s not really the case anymore in Western countries in that, now, no one needs to actively deceive anybody else in this way.
There were many heterosexual couples up until the 20th century, in England at least, who insisted that they were married (they weren't) and who called themselves “husband” and “wife.” As author Ginger Frost puts it, ironically of course, they were “living in sin” (cohabiting) because they could not marry legally, or they did not want to.
But what about queer and trans couples? The author of the best book on the subject, Jen Mannion, states that she wrote “about white working-class queer couples from the 18th and 19th centuries. The husbands were people assigned female at birth who transed gender, lived as men, and married a woman. Their stories are so important but most people didn’t even realize that queer/trans couples existed hundreds of years ago. Sadly, the only reason I was able to write the book was because of the newspaper articles that circulated when the husband was “outed” and the couple was usually subject to scrutiny, hostility, and sometimes violence.”
The term "Female Husband" dates back to the 17th Century, but it was first popularized by Henry Fielding, who worked as a magistrate when he wasn't writing Tom Jones and other books. His salacious 1746 book The Female Husband was based on the trial of one Mary Hamilton, who went under the name Charles Hamilton, who practiced as a physician. As Charles, "he" legally married Mary Price. In Fielding's book, a dildo puts in a repeated appearance, so we assume sex was involved.
But, two months later, Price reported Hamilton to the authorities, claiming she had been deceived. Legally, Hamilton had broken no laws, so "she" was charged with vagrancy, sentenced to hard labor, and publicly whipped in several towns. Above is an illustration from an 1813 edition of Fielding’s book. Hamilton may have ended up in Philadelphia, again working as a physician.
In the portrait at top, James Allen and his wife, Abigail, "were married for 21 years when he was killed in a work-related accident. When Allen’s biological sex was discovered post-mortem, Abigail claimed never to have seen him naked." (The New York Public Library)
This is not to be confused with a "Boston Marriage" which, to quote Wikipedia, "was, historically, the cohabitation of two wealthy women, independent of financial support from a man... Some of these relationships were romantic in nature and might now be considered a lesbian relationship; others were not."