Being filmed ruined a romance (2,6)
I believe the answer is:
on camera
'being filmed' is the definition.
(I've seen this before)
'ruined a romance' is the wordplay.
'ruined' indicates anagramming the letters.
'a'+'romance'='aromance'
'aromance' with letters rearranged gives 'ON CAMERA'.
(Other definitions for on camera that I've seen before include "In process of being filmed" , "Being shot" .)