Delayed, putting off day to get joined in marriage (6)

I believe the answer is:
allied
'joined in marriage' is the definition.
'allied' can be an answer for 'joined' (I've seen this before). I am not sure about the 'in marriage' bit.
'delayed putting off day' is the wordplay.
I cannot really see how this works, but
'day' could be 'd' (abbreviation for day) and 'd' is found within the answer.
The remaining letters 'allie' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'to get' is the link.
Can you help me to learn more?
(Other definitions for allied that I've seen before include "Owl's cry" , "Joined in friendship, treaty, etc" , "(Of nations) working together" , "in concert" , "Affiliated" .)
