More obscene husband and I parting through strain (8)

I believe the answer is:

filthier

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'more obscene' is the definition.
Both the answer and definition are comparative adjectives. Maybe they are linked in a way I don't understand?

'husband and i parting through strain' is the wordplay.
'husband' becomes 'h' (abbreviation).
'and' means one lot of letters go next to another.
'parting' indicates putting letters inside (inserted letters split or part another word).
'through strain' becomes 'filter' (synonyms. I am not sure about the 'through' bit.).
'h'+'i'='hi'
'hi' going within 'filter' is 'FILTHIER'.

Can you help me to learn more?

(Another definition for filthier that I've seen is " Disgustingly dirtier".)

I've seen this clue in The Guardian.

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