Ok, a minor breakthrough!
I have found Eula and Austin in the Fort Pierce, Florida, City Directory, 1922. So the marriage year would appear to be between 1920 and 1922 -- unless she was just using his last name, and they married closer to, or after the birth of Ned.
Sandra, do you have the actual divorce documents, or just the online index notation? In Australia divorce documents state the date of the marriage that is being dissolved.