Dude being lame to me for no reason

A guy I liked came to hang out with me and at first I thought he liked me first, but then he told me he’s “emotionally unavailable” but wants to be with this other girl. Although she’s not the only girl he likes (and was the one who showed him I liked him based on social media posts she saw while spying on me after looking me up online), he said she’s the one he wants to introduce to his family and that this was love he’s chasing. After leaving things alone, he came around saying he wants to be friends and I declined asking to be left alone because I needed space and time to get over my feelings for him. There were times we hung out but I needed to just get away from all of that as well as him saying he doesn’t have to do what I tell him to do and he will speak to me whenever he wants to. A month later he tried again and this time I just stopped responding to him whatsoever. He tends to stick his hands in my face to get attention and before he wouldn’t talk to me for days but then ask to call and ask me questions. He recently tried to re-add me on Facebook and I haven’t accepted. Why is he doing all this?

Also, we work at the same place and I have to see him everyday.