1. He may be in a state of poor mood or high stress, and needs some alone time to calm his emotions. At this time, not wanting to interact with others is not directed towards you personally.
2. He may be dissatisfied or disappointed with some of your actions or words, but for various reasons, he chooses not to communicate with you temporarily.
3. He may not be interested in your topic or request, or feel that it is unnecessary to continue the discussion, so he ends the conversation by saying 'I don't want to talk to you'.