Former partner was a model, it's revealed (7)
I believe the answer is:
exposed
'revealed' is the definition.
('expose' can be a synonym of 'reveal')
'former partner was a model' is the wordplay.
'former partner' becomes 'ex' (an ex-partner).
'was a model' becomes 'posed' (I've seen this before).
'ex'+'posed'='EXPOSED'
'it's' is the link.
(Other definitions for exposed that I've seen before include "Not hidden" , "Shown up" , "Not covered" , "Without cover" , "Made known" .)