It seems pretty obvious what ultimately happened here. Gisele dumped Tom for her fitness instructor. That sort of thing breaks up relationships all the time. I'm sure it stings for Tom but he's got so many other advantages in his life that I'm sure he'll get through it ok. And it's not why he retired from the NFL. However, if it is then he needs to hook up with some hottie twenty something model before March 15.
Not really new as we all knew that Giselle was pushing for the divorce. But it really seems like Brady wanted to stay together and got burnt out when he failed. Add in the worst coaching in his career, and that was the final nail in the coffin for hopes of another season.