is this a good enough reason...

Was it right for my bf well ex now he broke up with me because of his friend that told him i talk to him in class (he doesn't like when i talk to his friends) it was one sentence that i said to him one!! i feel like it was such a dumb reason and he just sees it as me lying but when he asked me if i did or not i said yes. Should i bother to try to fix things or let it go we have been together for about a year and a half now