Greatly upset about husband wallowing in idleness (8)
I believe the answer is:
lethargy
'idleness' is the definition.
(thesaurus)
'greatly upset about husband' is the wordplay.
'upset' indicates anagramming the letters.
'about' is an insertion indicator.
'husband' becomes 'h'.
'greatly' is an anagram of 'letargy'.
'letargy' placed around 'h' is 'LETHARGY'.
'wallowing in' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for lethargy that I've seen before include "Inertia" , "Sloth" , "Lassitude, languor" , "Being sluggish" , "Extreme lack of energy, listlessness" .)