A ballad gripping wife and son on every occasion (6)
I believe the answer is:
always
'on every occasion' is the definition.
(I've seen this before)
'a ballad gripping wife and son' is the wordplay.
'ballad' becomes 'lay' ('lay' can be a synonym of 'ballad').
'gripping' indicates putting letters inside.
'wife' becomes 'w'.
'and' is a charade indicator (letters next to each other).
'son' becomes 's'.
'lay' placed around 'w' is 'lway'.
'a'+'lway'+'s'='ALWAYS'
(Other definitions for always that I've seen before include "Evermore" , "At all times" , "For ever" , "Whatever happens!" , "In perpetuity" .)