Keeping, due to an attachment you've formed for? (8,2)

'keeping' is the definition.
The definition and answer can be both to do with fundamental existence as well as being present participle verbs.
Maybe they are linked in a way I don't understand?

'an attachment you've formed for?' is the wordplay.
I cannot really see how this works, but
'an' could be 'i' (Roman numeral for one) and 'i' is located in the answer.
'for?' could be 'to' (eg both can mean 'in the opinion of') and 'to' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

'due to' is the link.

Can you help me to learn more?