It's a great song. Yes, it is about wife-swapping.
John Prine also does a good cover of it with Iris Dement.
Milwaukee Here I Come is another of George Jones and melba Montgomery's, though Jerry Lee and Linda Gail Lewis do a better version. John Prine also covers it with Melba Montgomery.
Thanks for that Tom, I sort of thought it was but then wondered if it was just my twisted mind. Makes it all the better now I know the true context. Fantastic song