Make sure you're clear what's required by the bank, and what's by the hotel. The main requirement from AmEx is that the hotel is prepaid by the Platinum card owner (your spouse). That's enough for them to issue the credit. After that payment, your spouse will be the only listed traveler on the reservation.

The hotel will want to see the person checking in on that reservation. Your spouse will have to amend the list of travelers directly with the hotel. Although it's a simple task, AmEx Travel is not capable of doing it. Fortunately most hotels are interested in getting this business, and are unlikely to give you a hard time.