Perhaps one of the most shocking developments of the extramarital affair scandal that brought down CIA director and former Army four-star David Petraeus last November was the revelation that Marine Gen. John Allen, commander of U.S. allied forces in Afghanistan, was also under investigation for allegedly sending inappropriate emails to Tampa socialite Jill Kelley. After an exhaustive review of Allen’s email correspondence, he was cleared of any wrongdoing in January. But the damage had already been done to the reputation of the clean-cut general. He turned down the post of supreme allied commander at NATO earlier this month in favor…