Isn't it true that everyone reads their partner's messages so my boyfriend should let me?

My boyfriend refuses to let me read his messages between friends, saying that even if he gives consent, the people he's talking to have not. I said that is a weak excuse and everyone should assume that if someone is in a relationship their partner will be reading their messages, so it's fine.

Who is in the right here?

Isn't it true that everyone reads their partner's messages so my boyfriend should let me?
Post Opinion