Reese Witherspoon has mastered the impossible: getting along with her exes. "She is very close to Ryan [Phillippe]," a source exclusively tells Us Weekly. "They have been coparenting through the years, and they are friends." Witherspoon - who celebrated her milestone 50th birthday on March 22 - was married to Phillippe, 51, from June 1999 to October 2007. The Cruel Intentions costars share two children: daughter Ava, 26, and son Deacon, 22. "Since her divorce from Ryan, she has been supportive of her kids going into the entertainment industry," the insider says.