Boyfriend Doubts Me

My boyfriend checked my Google Drive account while I was sleeping. he reproached me about a sexy video I did for an ex. he was calm but upset because I didn't tell him but honestly, I totally forgot about that. I was so offended that he felt that it was his duty to remind me about that time of my life (before meeting him obviously) that I cried and shouted at his lil insecure ass. I feel bad because I reacted immaturely and out of rage. I think I reacted like someone who's been caught cheating. But I was always honest with him. What should I do? I refuse to apologize for something I did before meeting him. But I think I should apologize for my reaction.