Choose to adopt girl after partner's lack of care (7)
I believe the answer is:
neglect
'lack of care' is the definition.
(I've seen this before)
'choose to adopt girl after partner's' is the wordplay.
'choose' becomes 'elect' (electing is a kind of choosing).
'to adopt' is an insertion indicator.
'girl' becomes 'g'.
'after' is a charade indicator (letters next to each other).
'partner' becomes 'n'.
'elect' going around 'g' is 'eglect'.
'eglect' put after 'n' is 'NEGLECT'.
(Other definitions for neglect that I've seen before include "Ignore" , "Fail to act or take care" , "Failure to do something" , "lack of concern?" , "Heedlessness" .)