That woman's between partners -- it's a question of location (5)
I believe the answer is:
where
'a question of location' is the definition.
(I've seen this before)
'that woman's between partners' is the wordplay.
'that woman's' becomes 'her' (belonging to a woman).
'between' indicates putting letters inside.
'partners' becomes 'we' (West and East are partners in the game bridge).
'her' going into 'we' is 'WHERE'.
'it's' acts as a link.
(Other definitions for where that I've seen before include "enquiry" , "a question of location" , "At which point" , "In which position?" , "A question of place?" .)