In the past 40 or so years we laugh at that saying. Mainly because we don't know what it meant at its origins. I can't remember which war, ww1 or ww2, but anyway....Europe had so much death, destruction and no work that many women were so desperate, they had no other way to stay alive and to keep their children alive but to give sexual favors, i.e prostitute themselves to soldiers. In return she might get some k-ration(like a prepared meal in a tin tv dinner shape, which contained viands which were edible without cooking), a little money, whatever a soldier could afford to give and that included his boots. If he gave the woman his boots because she was barefoot in the winter, he either had an extra pair or knew he could get another pair if he was not to far from the supply lines. So back in the late 40's and early 1950's american young men would get into fights if one said your mother wears army boots is saying your mom is a ho.