I went through his phone...

26 (F) and 39 (M) together for 2 Years

I want to start this off by saying I am usually a firm believer in privacy and I believe looking through each others phones in relationships is a breach of privacy and shouldn't be done. Well.... about a week ago I was telling my partner about old flings trying to add me and message me on socials ( I hate hiding things) I told him how I blocked them but just wanted to tell him because not doing so felt like lying. He brought up a situation of him going through my phone one drunken night and finding old convos of before me and him got together but ultimately he didn't find anything (me cheating). For some reason I asked him if he's kept anything of his exes and by that I mean nudes etc. he told me no and even offered me his phone to look through, I told him no that I believed him. When he fell asleep something inside me told me I needed to see for myself.. sure enough in " my eyes only" I found old pictures (nudes) and s*x videos of old flings and an ex he claims to hate, in the same exact folder where he had photos and videos of me. When I saw this I felt very hurt, lied to, insecure, and stupid. I brought it up to him and he said that he didn't even know he had them that they have probably been in there forever but he never looks at them and said he didnt care if I deleted them. The issue for me is the fact that if you don't know if you have something why play it off as if you know that you don't. The fact that I was thrown into the same place with these other women knowing he's watched the stuff of me and trying to convince me you didn't know it was there seems like bullshit. The fact that he said he didn't care if I deleted them or that I should've... NO I shouldn't I feel as if I shouldn't have to be the one to do so. The same things he's done with me or asked me to do for him is the same exact stuff he was doing with these other women and now I just feel so many emotions and I can't stop thinking about it. I feel unimportant and now I feel like everytime we have sex him and these other women are going to be all I can think about. Being postpartum I'm already hard on myself and finding that just dropped my confidence so much more. Am I overreacting? has anyone dealt with something similar? How do I move on from feeling this way? TL;DR