Husband hopefully has power, owning two castles (2,5)
I believe the answer is:
mr right
'husband hopefully' is the definition.
'power owning two castles' is the wordplay.
'two castles' can mean two substitutions for 'castle'.
'power' becomes 'might' ('might' can be a synonym of 'power'**).
'owning' indicates putting letters inside.
'castle' becomes 'r' (abbreviation for rook/castle in chess).
'castle' becomes 'r' (abbreviation for rook/castle in chess).
'r'+'r'='rr'
'might' enclosing 'rr' is 'MR RIGHT'.
'has' is the link.
(Other definitions for mr right that I've seen before include "version of An Ideal Husband?" , "Perfect man (for someone)" , "Perfect husband" , "Ideal union candidate" , "great match" .)