With trouble, wife has endless long piece to iron (6)
I believe the answer is:
strife
'with trouble wife' is the definition.
('trouble and strife' is rhyming slang for wife)
'endless long piece to iron' is the wordplay.
'endless' means to remove the last letter.
'long piece' becomes 'strip' (long strip of material).
'to iron' becomes 'fe' (Fe is the chemical symbol for iron).
'strip' with its last letter removed is 'stri'.
'stri'+'fe'='STRIFE'
'has' is the link.
(Other definitions for strife that I've seen before include "Bitter disagreement" , "Discord and friction" , "Trouble and conflict" , "Conflict, dissension" , "Fighting" .)