If you are the primary on a credit card, and you give authorization for another on it, you are just as liable as whoever you gave permission to use the card. You can go after her in small claims court, but all she can say is that the charges were ok with him, and the judges most likely wont change that.
Unfortunate, but anyone you have on your card, if you have any doubts, cancell imediately.
You dont need to cancel all the cards, just her card.