If your doorbell is set up and working on your husband's account, he needs to use the "Invite home member" in the Google Home app on his phone to send you an invitation. (You'll need a gmail account.) Once you respond to the invitation, you should have access using your credentials to log into the Google Home app. You should not have to go through the setup process on your phone. (I'm just another Google Nest customer with one household member in addition to myself on my account.)
Just checking in to make sure that you've seen our responses. Please let me know if you have other questions or concerns as I will be locking this in 24 hours if I won't hear back from you again. Feel free to start a new thread and we'll be happy to help.