Our account is in my wife's name, sahe's a Diamond, but I do the bulk of the travel. We put both names on the reservation. No problem with either checking in, or having my stays credited to her account. The only down side is the occasional small 2 person premium charged at some of the bargain properties. ( some of the Hamptons, or HGI's charge a few dollars more for 2 people)
Yes there is a problem if we're staying concurrently in separate cities, but a phone call has usually resulted in credits for both stays.