Endanger former partner, model (6)
I believe the answer is:
expose
'endanger' is the definition.
(I know that endanger can be written as expose)
'former partner model' is the wordplay.
'former partner' becomes 'ex' (an ex-partner).
'model' becomes 'pose' (model can mean to pose).
'ex'+'pose'='EXPOSE'
(Other definitions for expose that I've seen before include "Unmask or denounce" , "article on scandal?" , "Make visible or obvious" , "display" , "Open to view" .)