Why did he tell me he has a girlfriend ofter me telling him that my crush and his friends like me?

There's this guy, who I've known for 2 years.
We've always been great friends and shared everything with each other and also supported each other at very hard times.
Then last year he thought I was in love with him, and created a little distance between us, because one of his friends secretely told me, that he only wants girlfriends for having sex, and didn't want me to get hurt because of him.
I decided to talk to him , and I so told him it wasn't true.
He said in response, that he just couldn't refuse me. Then many other guys began to get a crush on me, and I saw he didn't like it at all, seeing how many other guys gave me so much attention and me appreciating it.
After a while his friends told me, he always talked to them about how an amazing, sweet and beautiful girl I am, and that he was beginning to fall in love with me but too shy to tell me this.
I was playing hard to get, but since I thought he maybe was expecting me to take the first step, I couldn't wait any longer and dated others instead, so did he. He still keeps looking at my body, staring at me, and immediately looking away when he sees I saw him doing that.
Yesterday, we accidentally met at night, and we were having a great conversation.
He asked me where I was, and in responce I told him I was in a shisha bar.
He then asked me, if I was alone.
I seriously didn't get why he would ask any further, like it's not his business with who I go.
Then when I talked about my crush, told him that his friends were giving me compliments the whole time, and they all like me very much, he looked away.
He already knows who my crush is, so I guess he shouldn't have thought I maybe had a crush on him instead.
Then after that, he told me me he has a girlfriend since one month.
I didn't understand why he would talk about him having a girlfriend after me talking about my crush.
Is he trying to make me jealous, or just letting me know that I don't have a chance with him since he's taken?
But on the other side, I was talking about my crush, not about him at all, so why would he even try to give me a sign he already is taken and doesn't want to start anything with me?