How do I (20FTM) get my Boyfriend (18FTM) to understand privacy?

He wants access to all my social accounts (communication apps such as twitter(X),discord, even gaming accounts??) to just ‘see what he can find’. I have no problem showing it to him on my own phone, but I don’t feel comfortable letting him log in as it’s just for my own privacy and sometimes I just need to vent to friends about very personal things,not because I’m unfaithful. When I ask him why he wants it, he just says ‘I want to see things’ which makes me feel like he doesn’t trust me? And then he says I’m hiding something when I’d let him go through them. How do I explain to him I’d just like my privacy.

Extra Context: I’ve let him go through these apps and see what I say, to which he’s found nothing, and I don’t go through his stuff either.