The relationship between Tom Brady and Bill Belichick frayed to an extent at which the New England Patriots quarterback wasn’t sure of their future together and reached a point at which Brady “had enough of him,” according to a new book on the coach.

“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,” an unnamed source told ESPN’s Ian O’Connor, whose book, “Belichick: The Making of the Greatest Football Coach of All Time,” comes out next week. “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.”

The relationship between the two, one of the most successful in the history of pro football, deteriorated last season, with ESPN reporting that part of the fracture came from the presence and growing influence of Alex Guerrero, Brady’s training/lifestyle guru, around the team. In the offseason, Brady uncharacteristically stayed away from voluntary workouts with the team. It didn’t help that the Patriots lost the Super Bowl with one of their best defensive players benched for reasons Belichick has never explained. Brady admitted that losing that game in which he had passed for more than 500 yards “sucked” and, when asked in May by Jim Gray whether he feels appreciated by Kraft, Belichick and the Patriots, he drew laughs with his “I plead the Fifth” answer.

“Man, that is a tough question,” he continued. “I think everybody in general wants to be appreciated at work and in their professional life. There are a lot of people that appreciate me more than — way more than I ever would have thought was possible as part of my life. You have different influences in your life, and I think the people that I work with are trying to get the best out of me. They are trying to treat me in a way that is going to get the best out of me, and I have to get the best out of myself.

“What I am learning as I get older is it comes from within — the joy, the happiness — those things come from within the inside. To seek that from others, from outside influences, people you work with, people that cheer against you or cheer with you, I feel like it comes from within for me. I am trying to build up what is within me so I can be the best for me so that I can be the best for other people.”

Gray asked about Belichick, calling him a “fascinating man” and eliciting laughter from Brady, who did agree and added that Belichick “maximizes talent. What more could you ask for as a player? I wouldn’t be sitting here without his coaching.”

In the last installment of his “Tom vs. Time” Facebook series, Brady admitted: “The last couple years, a lot of parts about football weren’t enjoyable when they should have been. Some of it was my approach. And you know, I think any time you are together with people for a long period of time, relationships ebb and flow.”

And this is the NFL. Everyone knows how the story will end, whenever it ends. “It will end badly,” Tom Brady Sr. told Mark Leibovich for his book “Big Game: The NFL in Dangerous Times.” “It does end badly. It’s a cold business. And for as much as you want it to be familial, it isn’t.”