- he's in the right to pull out the "we're not dating card" since you're the one who initiated the, "it would never work out between us" topic.
- it's very possible that he meant what he said when he said it. When he told you he doesn't want to talk to her anymore, he could have been telling the truth.. Things happen, maybe they got together out of the blue. He would have been lying if he did not tell you that he was with her. You're discarding all the truth he has told you and focusing on one tiny thing that is likely a misunderstanding.
- he's not yours, he's free to date and see who he likes and you are free to see and date who you like. Making out with him was a decision you made with no strings attached... Since he's not your boyfriend and you're not his girlfriend and you've made it clear that a possible future relationship is out of the question.