Article lost by dirty man you're in a relationship with (5)
I believe the answer is:
uncle
'man you're in a relationship with' is the definition.
I can't judge whether this defines the answer.
'article lost by dirty' is the wordplay.
'article' becomes 'an' (indefinite article).
'lost by' is a deletion indicator.
'dirty' becomes 'unclean' (associated in meaning).
'unclean' with 'an' removed is 'UNCLE'.
Can you help me to learn more?
(Other definitions for uncle that I've seen before include "Grandfather's son" , "Dad's brother" , "takes the pledge" , "Brother of one's parent" , "Family relation" .)