Nightmarish ordeal -- married in station (7)
I believe the answer is:
'station' is the definition.
(type of social station)
'nightmarish ordeal married' is the wordplay.
'nightmarish' indicates an anagram (a nightmarish form of the letters).
'married' becomes 'm' (abbreviation, e.g. in genealogy).
'ordeal' with letters rearranged gives 'earldo'.
'in' is the link.
(Other definitions for earldom that I've seen before include "Aristocratic domain above a viscountcy but below a marquessate" , "Peer's domain" , "What sort of noble has" , "Dignity" , "Units" .)