Father upset with former partners giving tips (6)
I believe the answer is:
apexes
'tips' is the definition.
(apex can mean a tip or summit)
'father upset with former partners' is the wordplay.
'father' becomes 'pa' (pa can mean dad or father).
'upset' says the letters should be written in reverse.
'with' means one lot of letters go next to another.
'former partners' becomes 'exes' (ex-lovers).
'pa' written backwards gives 'ap'.
'ap'+'exes'='APEXES'
'giving' acts as a link.
(Other definitions for apexes that I've seen before include "Tips as of triangles" , "Summits, top points" , "Tips or highest points" , "Peaks, highest points" , "they're the tops!" .)