Former partner's preoccupied dear (9)
I believe the answer is:
expensive
'dear' is the definition.
(similar in meaning)
'former partner's preoccupied' is the wordplay.
'former partner' becomes 'ex' (an ex-partner).
'preoccupied' becomes 'pensive' (I've seen this before).
'ex'+'pensive'='EXPENSIVE'
(Other definitions for expensive that I've seen before include "Pricey" , "Costing a lot of money" , "Highly-priced" , "Very costly or dear" , "High in price" .)