This guy who has a crush on me...

So I’ve rejected this one guy a few times bc I simply don’t view him romantically and a few days ago I was eating at some restaurant with this guy I’ve been talking to for a few week (so I was on a date) and the crush guy saw me and the guy sitting outside and he starts yelling at the guy I was on a date with saying “he was not good enough for me” or something and lately(the crush guy) he’s been messaging me nonstop on social media asking over and over why I’m not attracted to him and why I wouldn’t have sex... i don’t know what to do... when I’m with the guy I’ve been on dates with, he’s ALSO getting annoyed too and I’m so happy with him and i don’t wanna lose him