Doubts about my relationship😓😞

My boyfriend and I have been dating for six months, but for several things we can not see each other very often. Today he told me that a month ago he started to like a classmate and that from that moment until now he likes more, she also likes him and my boyfriend told me that they have gone out together, invited her to the cinema, and they hold hands.

Should I leave him even if he says he doesn't want her to be his girlfriend?

Or am I just worrying too much?