Please read! my brother invaded my privacy! need opinion!?

im really upset. i came home tonight from work, i live by myself and came home, and when i sat down at my computer, i noticed a piece of paper that didnt belong to me, and it had websites on it like backpage and escort services,and when i got to looking at the piece of paper, i noticed its my brothers hand writing! i looked on my browsing history and noticed that it has been going on for almost two months now! he is going on sites, etc on my computer in my apartment. my brother use to work at the complex, and i guess still has a master key, and when i have been going to work at night, he has been coming into my apartment nightly looking at this stuff! i am furious to say the least. a friend of mine says im being to rash about it, but i dont think so. i wanted some opinions from people that dont know everyone involved. what should i do? how do i approach him on it? thanks so much!