Reveals models supporting former partner (7)
I believe the answer is:
exposes
'reveals' is the definition.
(exposing is a kind of revealing)
'models supporting former partner' is the wordplay.
'models' becomes 'poses' ('pose' can be a synonym of 'model').
'supporting' says to put letters next to each other (in a down clue, some letters go below others).
'former partner' becomes 'ex'.
'poses' after 'ex' is 'EXPOSES'.
(Other definitions for exposes that I've seen before include "scandalous revelations?" , "Deprives of cover" , "Reveals" , "Brings to light" , "Uncovers" .)