Heart perhaps in rogue broken by lover, finally (4)
I believe the answer is:
Here is my best explanation:
'heart perhaps' is the definition.
(heart is a kind of card)
'rogue broken by lover finally' is the subsidiary indication.
'rogue' becomes 'cad' (I've seen this before**).
'broken by' indicates putting letters inside.
'finally' says to take the final letters.
The final letter of 'lover' is 'r'.
'cad' placed around 'r' is 'card'.
'in' is the link.
(Other definitions for card that I've seen before include "Comb (wool)", "Bit of a wag - joker, perhaps", "Posted greeting", "Eg, a heart or club", "Heart or club, say?", "A bit of a wag", "Birthday greeting", "Stiff paper; plastic money", "Christmas greeting" and "Eccentric - stiff paper".)