Former lover, male, seen in bay, possibly desperate (7)
I believe the answer is:
extreme
'desperate' is the definition.
(thesaurus)
'former lover male seen in bay possibly' is the wordplay.
'former lover' becomes 'ex'.
'male' becomes 'm' (common abbreviation).
'seen in' is an insertion indicator.
'bay possibly' becomes 'tree' (bay is a kind of tree).
'm' going within 'tree' is 'treme'.
'ex'+'treme'='EXTREME'
(Other definitions for extreme that I've seen before include "Farthest limit" , "end" , "Very great; not usual" , "Greatest or smallest" , "Drastic -- limit" .)