Broke up with sweet date (8)
I believe the answer is:
crumbled
'broke up with sweet date' is the definition.
The definition and answer can be both related to change as well as being past participle verbs.
Perhaps there's a link between them I don't understand?
'broke up with sweet date' is the wordplay.
'broke up' becomes 'crumbed' (crumbing is a kind of breaking up).
'with' is an insertion indicator.
'sweet date' becomes 'l' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'crumbed' enclosing 'l' is 'CRUMBLED'.
Can you help me to learn more?
(Other definitions for crumbled that I've seen before include "went to pieces" , "fragmented" , "fell apart" .)