One must keep in mind that these women (Nadine, Milena, and every other model we lust after) do not exist solely to satisfy our own desires. They have lives of their own. Nadine, for example, is a mother.
Thirteen years is a heck of a long time in this business - how many of you have kept the same job for that long?
Let us thank them all for their fine work, and wish them well in whatever they choose to do next.