In some Asian Countries it is quite common for the wife to walk behind the male in traditional terms, I think it's mostly related to male chauvinistic Countries and a little old fashioned, then the term spreads like wild fire, if women follow their husbands around has a housewife, the term is a typical used between males, not women, for excess baggage, very disrespectful, because the men want to be with the boys and do what single men normally do.
Not everyone of course! My first thoughts was the cultural connection, of respect within certain races, normally all the women walk behind the male chinwagging(womans talk) at a leisurely pace. Not everyone would see it in a derogatory manner, more a figure of speech between males maybe, when a guy wants to be alone with his mates or wants to work away on assignment and a trailing wife sometimes effects the working environment, especially for expats and soldiers.
Here is a link on expats wives, I have not read it so I cannot comment on the article, but at a guess i would believe the term originated probably in the colonial days, women in a mens world type of thing, adopted by governments, when VIP's and soldiers were being posted over seas and such, the government sees it has excess baggage in the real term.
When i was getting divorced while in the military, i wasn't allowed compassionate leave, and was explicitly told it was a mans army and couldn't even defend myself until I was sent for by the courts, on the day, the divorce was issued. 1976, a trailing wife is a used to be a negative factor, that would have an impact on promotion prospects.
http://trailing-spouses.blogspot.com/