One who loves being unhappily married (7)
I believe the answer is:
admirer
'one who loves' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'unhappily married' is the wordplay.
'unhappily' is an anagram indicator.
'married' is an anagram of 'ADMIRER'.
'being' acts as a link.
Can you help me to learn more?
(Other definitions for admirer that I've seen before include "sweetheart" , "Person who fancies another" , "Married to one who cherishes" , "girlfriend?" , "One who thinks highly or romantically of" .)