Welcome to Rootschat. The best I can find may be worth a look, I would suggest you do not purchase any records before looking for more evidence . 
The 1921 census was taken on 21 June 1921, the marriage below, registered between April & June, may be a possibility.
Also two possible children. However I cannot find Catherine with this surname or the others on the 1921 register, I cannot find the children below later but others  may be able to help? 
Marriages Jun 1921    
George    Catherine   Isaac  Rees    Merthyr T.    11a   1183
      
REES, GWYNNETH       EDMUNDS  
GRO Reference: 1925  S Quarter in MERTHYR TYDFIL  Volume 11A  Page 1392
REES, VINCENT  HARDIE     EDMUNDS  
GRO Reference: 1923  M Quarter in MERTHYR TYDFIL  Volume 11A  Page 1402
Two possible deaths but there others later.
REES, CATHERINE       51  
GRO Reference: 1938  M Quarter in SWANSEA  Volume 11A  Page 1134
REES, CATHERINE       63  
GRO Reference: 1950  S Quarter in NEATH  Volume 08B  Page 376
Colin