When Winston is caught by the government, he is told that there are three stages to his "reintegration": learning, understanding, and acceptance. Winston doesn't betray Julia until the last stage and when he yells for the torturers to, "Do it to Julia! Not me!", he has capitulated and accepted Big Brother. The acceptance of Big Brother is essential to the government because it means that Winston no longer has free will; he is nothing more than a pawn of the government. Winston had thought he was strong and that he loved Julia. The government does not want any of the people to love anyone more than they love Big Brother and the government because that means that the individual might favor the one loved over the government. By betraying Julia, Winston shows that he loves the government, and Big Brother, more than anyone else.