Shrink gets paler as husband moves back (6)
I believe the answer is:
wither
'shrink' is the definition.
(I know that shrink can be written as wither)
I cannot understand how the rest of the clue works.
(Other definitions for wither that I've seen before include "(Of a plant) shrivel up" , "Lose moisture and die" , "decline" , "Writhe (anag.)" , "Dry up, become shrivelled" .)