Leave the thing to one's former spouse (4)
I believe the answer is:
exit
'leave' is the definition.
(I know that leave can be written as exit)
'thing to one's former spouse' is the wordplay.
I cannot really see how this works, but
'thing' could be 'it' and 'it' is found within the answer.
'former' could be 'ex' (prefix meaning former or onetime) and 'ex' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'the' is the link.
Can you help me to learn more?
(Other definitions for exit that I've seen before include "Sudden rush of pleasure" , "Way to leave" , "Depart" , "Way out sign" , "walk away" .)