The most common and most likely answer to this crossword clue is the 10 letter word EX-HUSBAND
I've seen this crossword clue in The Guardian
E
X
-
H
U
S
B
A
N
D
More clues leading to the result EX-HUSBAND
Buddy explains!
The straight part
We know that "partner no longer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case partner no longer = ex-husband.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EX-HUSBAND mean?
EX-HUSBAND noun- A former husband.