This image, for me anyway, demonstrates that children and other responsibilities do not strengthen a marriage in and of themselves. If anything, they increase the importance of a strong intimate relationship between the husband and wife, because they will likely suffer most when the wheels eventually come off.
How many spouses out there incessantly fuss over the passengers and the luggage, while unaware (or in denial) that the lack of regular attention being paid to the actual mechanics of the cart means that the whole damn thing is destined to lie in a ditch with the children and finances literally all over the place?