I’m not okay with this

my boyfriend and i are 15 and have had sex before. i know that word spreads, but only if someone tells someone. i specifically asked my boyfriend if he told anyone and he said no. but today i found out from one of my best friends, who i did not tell that we had sex, that my boyfriend told his friend (a girl) that we did. she told multiple people, my friends being some. i haven’t told a single person because that’s something private, so it bothers me that he lied to me and told someone. who, by the way, i don’t know at all. i want to talk to him about it but am i overreacting?

Edit: he always avoids walking by the people on the teams he plays on at school while we’re holding hands. and this never was something that bothered me but, it seems weird to me now that i know he told people. he doesn’t want to be seen displaying pda yet tells people we’re having sex knowing it could get to them? I understand that we’re young and it’s expected but i don’t feel like he’s respecting what i asked him not to do. also, we’ve been together for about 8 months