Credit Cards

I checked on my iPhone, iTunes and my account at apple.com and I cannot see a way of adding a second payment method. The only multiple methods seem to be gift cards as they are applied as a one-off.

The Apple support site also suggests you can only have one payment: Payment methods you can use in the iTunes Store, App Store, and iBooks Store - Apple Support

I don't believe that is possible to have multiple credit cards associated to an account at the same time.