Protection recommended at first in love affair (6)
I believe the answer is:
armour
'protection' is the definition.
(armour protects a warrior)
'recommended at first in love affair' is the wordplay.
'at first' suggests taking the first letters.
'in' is an insertion indicator.
'love affair' becomes 'amour' (I've seen this before).
The initial letter of 'recommended' is 'r'.
'r' going inside 'amour' is 'ARMOUR'.
(Other definitions for armour that I've seen before include "Suit of mail" , "Chain mail, e.g." , "Protection for a fighter" , "Body plate" , "Protective clothing" .)