New star, he wrote, sure to be the dominant partner (4,3,8)
I believe the answer is:
wear the trousers
'to be the dominant partner' is the definition.
I can't tell whether this definition defines the answer.
'new star he wrote sure' is the wordplay.
'new' indicates an anagram.
'star'+'he'+'wrote'+'sure'='starhewrotesure'
'starhewrotesure' anagrammed gives 'WEAR THE TROUSERS'.
Can you help me to learn more?
(Other definitions for wear the trousers that I've seen before include "Lead" , "shelter supporting members" , "Be the dominant one" , "Dominate the union" , "dominate partner?" .)