Is it the exact counterpart of another in married quarters? (6,4)

'is it the exact' is the definition.
I know nothing about this answer so I can't tell whether this works.

'counterpart of another in married quarters?' is the wordplay.
I cannot quite understand how this works, but
'counterpart' could be 'double' (I've seen this in another clue) and 'double' is present in the answer.
'of' could be 'o' and 'o' is present in the answer.
'another' could be 'r' (I've seen this in other clues) and 'r' is found in the answer.
'married' could be 'm' (abbreviation, e.g. in genealogy) and 'm' is found in the answer.
A single letter 'o' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...

Can you help me to learn more?