The most common and most likely answer to this crossword clue is the 8 letter word LOVELORN
I've seen this crossword clue in The Daily Telegraph
L
O
V
E
L
O
R
N
More clues leading to the result LOVELORN
Buddy explains!

The straight part
We know that "in need of affection" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in need of affection = lovelorn.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 LOVELORN mean?
LOVELORN noun- A person who is lovelorn.
- Abandoned or forsaken by one's lover; having constant bad luck in romance; desperate for love.
- Unloved, bereft of love.