No longer blame former lover I esteem (9)
I believe the answer is:
exonerate
'no longer blame' is the definition.
'former lover i esteem' is the wordplay.
'former lover' becomes 'ex'.
'i' becomes 'one' ('one' can be a synonym of 'i').
'esteem' becomes 'rate'.
'ex'+'one'+'rate'='EXONERATE'
(Other definitions for exonerate that I've seen before include "Free of duty" , "let off the hook" , "Discharge" , "Excuse" , "Declare to be blameless (9)" .)