My Dad did the same watching City and the Rags in the 1950's , but after the Munich air disaster he chose to only go to Maine Rd. , when i asked him why , he just said things had changed but never got to the bottom of it.
The Munich disaster probably got the Rags loads more fans with the sympathy element , maybe a lot of outsiders started going to the Swamp for morbid curioisity , mysteriously my Dad went the other way and never stepped inside the Swamp again after Feb 1958 , he had his reasons but he never shared them