His wife possibly brings endless woe to him (3)
I believe the answer is:
man
This could be a double definition.
'his' is the first definition.
(thesaurus)
'wife possibly brings endless woe to him' is the second definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
Can you help me to learn more?
(Other definitions for man that I've seen before include "race" , "Isle of ..., ... o'war" , "Bloke" , "Isle of . . ., . . . o' war" , "The most destructive and polluting animal" .)