I need some insight, how do I prove to someone I love them?

I am very forgetful and I also have a lot of pictures involving family, friends, and myself on all social media platforms. When my ex and I broke up, I made sure to delete all remaining comments, pictures, and posts about him. I've been dating someone new (my current bf) for 10 months now and he manages to dig deep into my profiles and find traces of my ex I forgot to delete. (back then, social media was very big for my ex and I). Sometimes there would be a comment I forgot, or a picture, etc. Thing is, Im all about my current boyfriend now. When he brought it up to me, I apologized and told him I'd take care of it. However, it seems to be an occurring issue and it isnt like I didnt want to delete the pictures. 

I've made new profiles just to make sure everything was deleted. But still my current boyfriend manages to dig deep into them enough to find something. Yesterday, he dug through my snapchat that I've had for 4 years now (all my family memories, highschool, etc. are on there). Thats the reason I kept it, for memories. And he found some pictures of my ex, he got mad at me for it and assumed I wasnt over him since it wasnt the first time. But I always assure him it's because I end up having over a million photos and I obviously cant get to them all. I didnt get mad at him nor did I try to make an excuse but he insists me "forgetting" has become an excuse. He tried to leave me over it saying I "never" changed and I never forgot about my ex. 

Please help. I am over my ex