The best solution to this is to include your master password for your password manager (you are using a password manager, right?) in your will. Registering this information with your lawyer is a pretty safe place to put it, and you can ensure it won't be shared until you are incapacitated or no longer living. The alternative is to have your digital identity and property die with you. Some might legitimately choose this option instead.
Both are options. I use a password manager, and it would be simple to have two password archives. One is everything I want to grant access to and one things I'd rather see die with me. So if I want to give access to my email and online banking, I put that in one, but put things like Twitter in the other. I probably should arrange this. I haven't given anyone the password to my passwords but probably should. I'd trust my brother, and between trust and lack of physical access, I'd be comfortable with the security.