How can I find out who is accessing my Yahoo email?

I have been noticing that new email that I've received, and not yet opened, are marked as if they were already read. Both in my inbox and in my sent box. It is very strange, and I'd like to know if I can find out who is accessing my email and from where they are doing it?

How can I find out who is accessing my Yahoo email?
i dont tink its possible if you think someone is reading it just change your password and if it sends you a message with your new password delete that message so the person cant read it when they log in then they cant log into yours anymore
Reply:Just change your password. Maybe it's your boyfriend/husband?