One of the tough things about early adolescence is that the main criteria for "liking" someone seems to be that they like you. This guy did not have strong feelings about you when he kissed you, maybe was just intrigued because you liked him. He sounds like he's more interested in the other girl but doesn't want to burn his bridges in case he later decides you're worth toying with some more. He probably isn't being manipulative, he just doesn't know how to behave.
Unfortunately, he got under your skin and how you're thinking about him a lot. Our imaginations and wishes aren't easy to control! Even when we know our affection is misplaced, it is hard to make our heart do our bidding.
Did you ever hear an adult say "I wouldn't be a teen again for all the world!" -- well this is why. As you have more encounters with boys, you'll start to learn more about what a healthy, meaningful relationship is. It can't be rushed, and is based on honesty, caring about the other's feelings, and talking directly to each other, not through a friend-of-a-friend. (Not to say you'll never be lied to, to your face...)
Chin up dear, you'll find someone who deserves you!