Why did he text me & follow me back now that I have a boyfriend?

this guy i was head over heels for had a crush on me & we would hang out everyday but we both found out we couldn’t date for a personal reason but i kept on trying & he would unfollow me each time to help me move on. months past & i have a boyfriend now & i added him only to asks a question about something he sells & we never talked after that & he hasn’t unfollowed me & he watches every story & eventually reached out to me in the morning saying hey but i just left him on read. like why try after i have a boyfriend lol..
Why did he text me & follow me back now that I have a boyfriend?
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