login/logout

I have a page that I only want members to see.
I have used the wordpress – make this page password protected.
This worked until I changed pages and went back. the page was still sitting there for all to see. I have even logged out and in again and I could still see that page. Without having to do caching, what are the alternatives. There should be a logout, so if another user looks at my pc then they see the contents of that page.
Is it possible to have a logout of the page to prevent other users looking at this page.