You can cover yourself and your partner or spouse if aged between 18 - 74 years old. (aig.ie)
An authorized user is usually a child or spouse of the primary cardholder, but it can be anyone whose name the primary cardholder agrees to add to the account. (speakingofcredit.com)
An authorized user is usually a child or spouse of the primary cardholder, but it can be anyone whose name the primary cardholder agrees to add to the account. (creditcards.com)