Save one’s partner? (7)
I believe the answer is:
husband
I believe this is a double definition.
'save' is the first definition.
(as in husbanding or saving one's resources)
'one's partner?' is the second definition.
(male spouse)
(Other definitions for husband that I've seen before include "Partner in marriage" , "Better half's other half?" , "Man United" , "Make careful use of" , "manage wisely" .)