I do 98% of my banking/bill paying online. I'm also the one in my marriage who handles the bill paying. My husband is in charge of starting up service when we need it and we alternate calling in when there's a problem. This system works for us in every way but one- passwords.
For my personal accounts I use a system with a word (ie green) a number (ie 49) and the domain name of the sight. So at Bank of America my password would be green49boa. The root stays the same but the domain name makes each individual password unique.
My husband rotates through 3-4 passwords that look something like ThYgIfRk. Something I will never ever ever remember.
We've tried coming up with a root to use my system, but all of the things we can agree on I think anyone else could easily figure out if they know basics of our life (or take a look at facebook).
This is slightly irritating when I have to call Comcast or Verizon to deal with a service issue. The greater problem is this doesn't pass the 'hit by a bus test.' If I got hit by a bus tomorrow my husband wouldn't be able to get onto most of our online accounts.
So how do you share this info? Do you create a password together? Is there a piece of paper buried somewhere in your house with all of the passwords written down? Do you just not worry?