Aaaaand I just realized the joke is she's chastising him for "acting helpless" when that's probably exactly what she's doing... Had to come back to comment once it hit me
In a time when women wore corsets, bending down to tie a shoe was not possible as their range of movement was restricted. There was a motto when getting dressed: "shoes before corset". Men's clothing allowed for more movement as they were expected to be active. Exercise and fitness for women was frowned upon as there was concern it would disrupt their ability to have babies (no joke- this was the "medical" opinion of the time).
This is it. Married thirst is best thirst. "Just wait until we arrive at our humble but respectable domicile, where I shall tie your shoe and we will enjoy connubial bliss."