I am cut by the heartless couple (4)
I believe the answer is:
item
'couple' is the definition.
(a romantic couple are 'an item')
'i am cut by the heartless' is the wordplay.
'i am' becomes 'I'm' (contraction).
'cut by' means one lot of letters goes inside another (some letters cut their way into a word).
'heartless' suggests removing the centre.
'the' with its centre taken out is 'te'.
'im' enclosing 'te' is 'ITEM'.
(Other definitions for item that I've seen before include "newspaper article" , "Two people romantically linked" , "One thing on a list" , "Individual unit in a list" , "Syrian capital" .)