Why is this guy I hooked up with still watching my story?

Back then we both realized I used to date his friend so we couldn’t date. but we did talk on and off and it brought mixed signals to the point where he would just hit me up for sex & give me kisses on the cheek, get jealous, one day.. lol. Now I have a boyfriend and he’s watching every story I post it’s odd.
Why is this guy I hooked up with still watching my story?
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