what does it mean if your bf hangs out with other girls??

me and my boyfriend were talking all hari yesterday and he told me these girls at his hotel he was staying at on vacation were following him and telling him he was cute. he didnt like them and thought they were weird and he told them i was his girlfriend. they all berkata 'oh..' but today we were talking and then he stopped texting me back. then n jam later i berkata 'hello?' and he berkata hi im hanging out with those girls and then i berkata 'oh....well ill stop bothering anda and ill let anda hang out with them...bye' and he replied 'ok bye haha'. its really bothering and upsetting me cause he doesnt even know them, yet hes hanging out with them (theres like 10 girls) and he wouldnt even bother texting me back and weve known each other forever. weve never hung out before. i dont think he knows how much it bothers me though, since im usually not the jealous type. what does it mean if he hangs out with other girls and how should i get over it?? (oh and btw im just having an off hari today) thanks so much and no rude comments!