I need input on a boyfriend issue

So I was at my boyfriends house the other day and he had to leave for baseball practice but said that I could just stay and hangout in his room till he got back. I was alone there for a couple hours and so i got a bit curious and just started looking around. I wasn’t doing it with any negative or suspicious intentions, I was simply just bored. There’s a shoe box sitting on top of his dresser and I opened it to find some of his ex gfs belongings including a necklace charm with her initial, glasses... We’ve been dating for almost a year now and I feel as though he should have disposed of or gotten rid of those items by now. I’m not sure how to feel about it or if I should be upset or not. I know I have a bracelet from my ex boyfriend laying around somewhere in my room but idek where it is and I just keep forgetting to toss it. I want to believe that this is the case with him as well but her stuff is in a box sitting out in the open in his room. There’s no way he just forgot that all of it is in there when he literally sees the box everyday. Am I just overthinking all of this or is there a reason he has kept it. He’s the one that broke up with her and they ended on bad terms. She’s not a nice person and has spoken badly about me to him and other people, calling me names and such, simply because I am with him now. They have absolutely no verbal contact with each other but do see eachother at school from time to time. I don’t believe he still has feelings for her but why would he keep her stuff?