SWMBO is an acronym with a specific origin. The referenced term, "She Who Must Be Obeyed," was the consistent reference used by Horace Rumpole, the British barrister who was the protagonist of a number of short stories (which I can recommend), collectively known as "Rumpole of the Bailey," by John Mortimer. Rumpole (portrayed by Leo McKern in the BBC series of the same name) is an incorrigible defender of any and all clients, a devotee of the bottle, and always refers to his wife Hilda as "SWMBO."
“Malt does more than Milton can / To justify God’s ways to man”
-A. E. Housman (1859–1936). A Shropshire Lad , 1896.