Ultimate in disappointment, wife getting diamonds another time (5)
I believe the answer is:
twice
'another time' is the definition.
(I've seen this in another clue)
'ultimate in disappointment wife getting diamonds' is the wordplay.
'ultimate in' suggests the final letters.
'wife' becomes 'w' (abbreviation).
'getting' is a charade indicator (letters next to each other).
'diamonds' becomes 'ice' (slang term for diamonds).
The final letter of 'disappointment' is 't'.
't'+'w'+'ice'='TWICE'
(Other definitions for twice that I've seen before include "Two times" , "Doubly" , "Double in quantity" , "You only live -- (film)" .)