Former lover with a bit of work starts to upstage everyone in area of date (7)
I believe the answer is:
exergue
'area of date' is the definition.
(area on a coin where a date might be inscribed)
'former lover with a bit of work starts to upstage everyone' is the wordplay.
'former lover' becomes 'ex'.
'with' says to put letters next to each other.
'a bit of work' becomes 'erg' (unit of work in physics).
'starts to' indicates taking the first letters.
The initial letters of 'upstage everyone' is 'ue'.
'ex'+'erg'+'ue'='EXERGUE'
'in' is the link.
(Another definition for exergue that I've seen is " Space on medal".)