What did Cohn reveal?

Chapter V:

In the morning, Jake goes out for breakfast, observes Paris in the morning, and goes to work. He goes to an insignificant press conference and shares a taxi back with two colleagues. When he returns to work, Cohn is waiting for him. They lunch together. Cohn is having writer's block, but he can't go to South America because Frances won't let him. Cohn asks him about Brett. Jake says she's getting a divorce now and is going to marry Mike Campbell, who is currently in Scotland. Cohn admits he is falling in love with her.