Considering the 1950 census required a visit by the census taker, I posit the word “partner” was written at the request of one or both ladies, depending on whom gave the information. Quite simply, questions were asked, answered, and written. Bear in mind that the census takers would have encountered a multitude of households that would not conform to the proverbial husband, wife, and two children households. Most would doubtful give it a second thought. You’ll never know what the two ladies may have thought by using the word “partner”. But it certainly appears the word was used as a term of endearment, without being too specific. Bravo to hem!