Bonus miles will only go to the primary card holder. Any points earned from spending will apply from either cards.

Are you just looking for an AA credit card? If so, why don't both of you apply for the Citi AA cards? You can look for the topics for them in the forum here where users churned these cards. See here.

If you have a lot of spending in other categories, you can look into opening other credit cards that offer more points.