Express relief when he comes between two wives (4)
I believe the answer is:
whew
'express relief when' is the definition.
I can't tell whether this defines the answer.
'he comes between two wives' is the wordplay.
'two wives' can mean two substitutions for 'wife'.
'comes between' indicates putting letters inside (I've seen this in other clues).
'wife' becomes 'w' (abbreviation).
'wife' becomes 'w' (abbreviation).
'w'+'w'='ww'
'he' placed inside 'ww' is 'WHEW'.
Can you help me to learn more?
(Other definitions for whew that I've seen before include "Expression of relief" , "expression of surprise" , "Bustle about" .)