Orwell chiefly uses betrayal at the end of the novel. After Winston's torture stops, he is left alone most of the time. He sleeps, he is given three meals a day, and he dreams of the Golden Country, a place he associates with Julia. One night, he reveals his loneliness and deep yearning for her as he cries out in his sleep:
Julia! Julia! Julia, my love! Julia!
He wakes up and longs for in a way he never did when they were together, revealing the depth of his loneliness in prison—and yet at the same time, shows he still feels connected to her:
For a moment he had had an overwhelming hallucination of her presence. She had seemed to be not merely with him, but inside him. It was as though she had got into the texture of his skin. In that moment he had loved her far more than he had ever done when they were together and free.
He had promised himself that no matter what happened to him in the Ministry of Love, no matter what he said or confessed, that he would never betray Julia. Yet he does betray her.
This betrayal destroys their relationship. She too betrays him in prison. When they meet on the streets later, they are each profoundly alone. They each confess their betrayal to the other. Julia says,
You WANT it to happen to the other person. You don’t give a damn what they suffer. All you care about is yourself.
All you care about is yourself ... And after that, you don’t feel the same towards the other person any longer.
There did not seem to be anything more to say.
Winston's love has been emptied out because of his betrayal. He wants nothing more than to get away from Julia:
He was overwhelmed by a desire not so much to get away from Julia as to get back to the Chestnut Tree Cafe, which had never seemed so attractive as at this moment. He had a nostalgic vision of his corner table, with the newspaper and the chessboard and the everflowing gin.
The Party is determined to divide people from one another so that they will have nothing to turn to in their loneliness but Big Brother. Julia and Winston's relationship was a threat that the Party was willing to go to extremes to destroy.