How to ask for reassurance?

I’ve been dating my bf for two and a half years and idk i’ve been feeling extra insecure lately. he hasn’t done anything wrong but I just feel super sad and keep thinking he’s gonna leave me. just as of today. I know it will eventually pass, it may just be my hormones, and I don’t wanna show him im this insecure. I think it’s because i’ve been subscribed to the #breakups reddit page and been reading all these stories… it’s really scaring me. ive unfollowed the page just now. is there a way I could ask or communication this to him without sounding pathetic??