Love, once I've become attached, has a wearing effect (4)
I believe the answer is:
eros
'love' is the definition.
(Greek god of love)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for eros that I've seen before include "divinity" , "very centre of London?" , "Cupid, son of Aphrodite" , "Cupid, to the Greeks" , "God of love - example of 1 down" .)