make things official. but the paperwork was never filed. raising eyebrows inside of the white house about why. >> i can't tell you how long the process is supposed to work. >> reporter: and now cnn learned the resignation came amid details of a contentious divorce including an allegation that he hit her during a dispute nine years ago, an allegation that shanahan has denied. his ex-wife was arrested and charged with assault and the charges were later dropped. in a statement today shanahan said he was resigned to protect his children. writing, i would welcome the opportunity to be secretary of defense but not at the expense of being a good father. the sudden withdrawal leaves the pentagon without a permanent leader amid escalating tensions with iran. >> president trump has said very clearly he doesn't want to go to war. >> reporter: the drama also coming as the president heads to orlando, florida, to launch his re-election bid in front of 20,000 people. >> we will make america great