An insider shared: "He is beside himself and has been crying. He was completely caught off guard and blindsided and had no idea she would do this.
"Angelina filed the court papers a minute before the courts closed on Monday night. He didn't have a lawyer or anything. She had threatened divorce in the past but he did not think she would file this time. He is completely devastated and beside himself. He is a shattered man.
"He's extremely upset. But he is totally focused on just being helpful and making sure his kids are doing as well as possible."
And Brad is reportedly disappointed their split had to "play out publicly".
A pal added: "He is emotionally torn. Right now, he is devastated. He still loved Angelina and would have preferred they fight to make the marriage work. He was willing to do whatever it took to save the marriage and didn't know Angelina had already given up on it. He has wanted to protect the children. He didn't want it to play out publicly."
Maddox Jolie-Pitt, , Angelina Jolie and Brad Pitt. Photo / AP
Angelina filed for divorce from Brad last Monday, citing "irreconcilable differences". The By The Sea actress is seeking joint legal custody but sole physical custody of their six children, Maddox, 15, Pax, 12, Zahara, 11, Shiloh, 10, and eight-year-old twins Knox and Vivienne.