Bf's baby's mama's stuff still in his apartmentji?

So my bf and I have been dating almost a year now. We met at work when he was originally with his now ex. They have a child together and they were together about 5 years. The child is about a year old. Yes he did leave soon after the baby was born. So there is some baby mama drama for sure. We recently had an argument ove some stuff she still had in the bathroom closet; a bathrobe, make up, perfume, etc. There are also old love notes, notebooks of them in random places all over the apartment. Some old dead rose hanging on the wall, etc. I expressed she needs to take that stuff to her current home which is now a room at her moms house. He told me she doesn't have room for this stuff and argued with me and got very defensive. I asked him to give this stuff back to her. Most of the stuff was gone except a few items. I went to put his coat away in the coat closet and found it all in there. Got upset and he got mad ate saying I was going through his stuff. Which is rediculous again being defensive. I tried to compromise and said fine just keep her stuff out of site in a box and put the notes away. We agreed. But I feel this stuff has no place at his apartment and she should make room for it and she had previuosly asked to have the notebooks anyway... Am I right here or is he?