Just son supporting a female's romantic flings (7)
I believe the answer is:
affairs
'romantic flings' is the definition.
'just son supporting a female's' is the wordplay.
'just' becomes 'fair' (just can mean fair in the sense of showing justice).
'son' becomes 's'.
'supporting' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'a female' becomes 'af' (I've seen this in other clues).
'fair'+'s'='fairs'
'fairs' after 'af' is 'AFFAIRS'.
(Other definitions for affairs that I've seen before include "Current ones are of interest to the public" , "Business; amours" , "Business and financial dealings" .)