Why would he ask me this if he has someone else?

He used to like me and I used to like him(I had rejected him POLITELY in Dec. basically he said "Oh, I think you have a crush on me" and I said I didn't. I regret rejecting and please don't lecture me on that) Despite that, he tried again to get me to notice him in case if he can get another chance, usually by singing or asking questions, etc.,. It's February now(obviously)-so he told/asked me last week that he had a crush on so-and-so(trust me, I would believe it because she and him talk a lot and she seems really into him). And then he asked if I was okay with it. I said yes. Two days later he ignored me and was a bit hostile in his jokes. Then he was straight up hostile. The day after he was the same and wasn't trying to get me to notice him so clearly he was now distancing himself. He even said it was fine if I didn't talk to him because of etc. Today, I heard him say right in front of me that his heart belongs to so-and-so *rolls eyes.* I don't understand-if he is into this girl and apparently "over me" by declaring his fondness for someone else than why did he ASK me if I was okay him liking someone else? thanks. BTW, SHE AND HIM have been talking a LOT...nearly two months.