Marine Gen. John Allen, former commander of allied forces in Afghanistan, will retire from the military to care for his ailing wife. President Barack Obama, who had nominated Allen to head NATO, met with the departing officer on Tuesday and accepted his request to leave the armed forces, the White House said.

Obama had nominated Allen to be Supreme Allied Commander Europe and Commander of the U.S. European Command in October 2012. But that move went on hold while the Pentagon’s inspector general looked into Allen's email contacts with a Tampa socialite linked to the scandal that led to CIA Director David Petraeus’ resignation. Allen was cleared of any wrongdoing, and his confirmation was unlikely to run into trouble in the Senate.

“Today, I met with General John Allen and accepted his request to retire from the military so that he can address health issues within his family,” Obama said in a written statement.

“I told General Allen that he has my deep, personal appreciation for his extraordinary service over the last 19 months in Afghanistan, as well as his decades of service in the United States Marine Corps,” the president said.

Obama praised Allen for overseeing “the significant growth” in Afghan security forces, continued “degradation” of al-Qaida and its Islamist allies, and the shift of security responsibility to Afghanistan’s military and police—a linchpin of the president’s NATO-backed plan to pull American forces out by the end of 2014.

“He worked tirelessly to strengthen our coalition through his leadership of the International Security Assistance Force (ISAF), and to improve our relations with the Afghan government,” Obama said.

“Above all, he cares deeply for the men and women in uniform who serve our nation—as well as their families—and I am grateful for the sacrifices made by his family in supporting him during his service. John Allen is one of America’s finest military leaders, a true patriot, and a man I have come to respect greatly,” the president said.

He added, “I wish him and his family the very best as they begin this new chapter, and we will carry forward the extraordinary work that General Allen led in Afghanistan."

Allen’s wife, Kathy, is very ill with a combination of chronic health issues that include an autoimmune disorder, the Washington Post reported.