Affected to have led a model life (5)
I believe the answer is:
posed
'affected to have led a' is the definition.
I can't tell whether this definition defines the answer.
'model life' is the wordplay.
'model' becomes 'pose' (model can mean to pose).
'life' becomes 'd' (I can't explain this - if you can you should give a lot more credence to this answer).
'pose'+'d'='POSED'
Can you help me to learn more?
(Other definitions for posed that I've seen before include "Modelled" , "Struck attitude, perhaps for painter" , "Presented (a question)" , "Was a model" , "Faced the camera" .)