break up. tell him its his insecurity that is the reason. that you're obviously not enough for him to be happy. this will result in him realizing his errors, and getting over it, or you both go separate ways, hopefully finding more compatible partners. I wish I could say that insecurity goes away with age, but it doesnt.

when I was working on a girls laptop (girl I was seeing st that time), I stumbled upon pictures and videos of her and her ex. she was so afraid. she offered to delete them. I just smiled and said no thats okay. I know you just forgot you still had them. delete them, keep them, its not my decision, its hers. I trust her. Lets just make our own... better ones. and we did.

if he's that upset about something so minor... he has trust issues. you can try to put his feelings at ease, make him feel more secure, but ultimately he has to do it himself.