How can I create a separate address book to sync to a different mobile phone?
Create a separate user account for your husband. Your stuff will be different. Steps:


System Preferences > Users and Groups.
Click the lock icon in the bottom left and fill in your password.
Click the + below the left pane.
Fill in the credentials.
Log in to that account and start filling out the contacts.
If you want to copy over any contact, select the contacts in the address book and then File > Export. Save the files on a USB drive or a place not in your home directory.
Just open the files in your husband’s account. They will be added to Contacts.


If you are talking about an iPhone, another thing you could do is use iCloud. That would be much better and much more streamlined.