Tom Brady felt trapped this past offseason and wasn't sure if he wanted to play for Bill Belichick anymore, according to a new book on the coach's life.

"If you're married 18 years to a grouchy person who gets under your skin and never compliments you, after a while you want to divorce him," a source with knowledge of the Brady-Belichick relationship told ESPN's Ian O'Connor, author of "Belichick: The Making of the Greatest Football Coach of All Time," after the 2017 season.

"Tom knows Bill is the best coach in the league, but he's had enough of him. If Tom could, I think he would divorce him."

O'Connor interviewed 350 people (Belichick didn't cooperate) and reports in the book that Brady was so upset with his coach that he still wasn't certain in late March if he would return to the New England Patriots.

"But in the end, even if he wanted to, Brady could not walk away from the game, and he could not ask for a trade," O'Connor wrote. "The moment Belichick moved [Jimmy] Garoppolo to San Francisco, and banked on Brady's oft-stated desire to play at least into his mid-forties, was the moment Brady was virtually locked into suiting up next season and beyond. Had he retired or requested a trade, he would have risked turning an adoring New England public into an angry mob."