Affectionate wife's getting a room (4)
I believe the answer is:
warm
'affectionate' is the definition.
(synonyms)
'wife's getting a room' is the wordplay.
'wife' becomes 'w' (abbreviation).
'getting' is a charade indicator (letters next to each other).
'room' becomes 'rm' (abbreviation for room).
'w'+'a'+'rm'='WARM'
(Other definitions for warm that I've seen before include "Intimate - with a comfortable temperature" , "Lively" , "easily aroused" , "Animated" , "Getting close to target" .)