Loooong question, sorry... But someone good at reading male minds, please help!?

[Devin R]

He's totally using you to get what he wants. He's playing a game with you. The more you obssess over him, the more control he has over you. I would bet he is looking to "play the field." There is most certainly someone else, you said it yourself, he's using both of you. He is stringing you along until he can find someone else to completely take advantage of, then he'll end it with you permanently.