Say nothing! Husband is always primarily going on about himself (8)
I believe the answer is:
egomania
'primarily going on about himself' is the definition.
I can't judge whether this defines the answer.
'say nothing husband is always' is the wordplay.
'say' becomes 'eg' (both can mean for example).
'nothing' becomes 'O' (looks like zero - 0).
'husband' becomes 'man' (a married man).
'is always' becomes 'ia' (this might be a standard abbreviation of which I'm unaware).
'eg'+'o'+'man'+'ia'='EGOMANIA'
Can you help me to learn more?
(Other definitions for egomania that I've seen before include "not caring about others" , "Thinking of oneself" , "Abnormally excessive opinion of oneself, quite mad" , "Obsessive self-centredness" , "Intense and irresistible love for yourself" .)