Welcome to Android Central! When he first set up his phone, was it your Google account that was originally signed into?
Go to Settings>Accounts, select your Google account, then remove it. If your husband never signed in with his own Google account, then he actually may want do to a full factory reset (backing up any important data first), and then use his own Google account during the initial Setup Wizard.
If this is a situation where he is using it to spy on you and won't give you physical access to remove your Gmail from his phone your can remotely log out of it without touching his phone, than change your password to ensure he doesn't log back in.