should i be jealous? or does it even count as he cheated?

a few months ago, he admitted that he had a crush on my close friend, i was hurt of course, then he said he doesnt feel it anymore. and today, he went to a convention. not supposedly with her, but he met her there and hung out with her. i dont know what to do:( is this supposed to not hurt? because im on my pms right now 😥😥😥