I didn't realize you were talking about UK records. I did a Google search on "Wales divorce records" and found the following:
http://www.nationalarchives.gov.uk/records/looking-for-perso...If you go to the section on decrees absolute, it gives directions for obtaining a divorce record. The fee is pretty steep, so you will have to decide whether it is worth it.
I also checked freebmd.org,uk and found three marriages listed for David Rowberry: one in 1940 to Caroline Bevan, one in 1953 to Phyllis Hook, and one in 1954 to Marian Gibbs.