Apparently I'm overreacting because I got annoyed that my BF was telling his mom about my ex and how…

Apparently I'm overreacting because I got annoyed that my BF was telling his mom about my ex and how he was "big" and how I liked a picture last year of his when me and my BF were broken up and calling me a liar saying we were together. Basically making me sound like a cheater to his mom and friends. So he went on my exs Insta and went to the picture to find the date. And I'm the one that's wrong for getting mad that he had to go do all that.