Love affair so begins, finally finding god (4)
I believe the answer is:
eros
'god' is the definition.
(Eros is an example)
'love affair so begins finally' is the wordplay.
'finally' suggests the final letters.
The final letters of 'love affair so begins' are 'EROS'.
'finding' acts as a link.
(Other definitions for eros that I've seen before include "One worshipped" , "capital statue" , "Pagan god" , "asteroid four hundred and thirty three" , "God of love - example of 1 down" .)