The Answer

Y : "Why do you wanna be with me?"

X : "Cause I need u."

Y : "No." (showing a disagreement by shaking his head)

X : (confused) --Is it wrong?---" Why do you wanna be with me?"

Y : "I stay with you because I love you, not because I need you."

3 words: Same subject and object (I and U),yet that word in between can be really manipulative to anybody who said it or meant it.
By the time, the word 'need' was meant to be 'love'. But sometimes, a word can be meaning with just what the basic meaning of that word itself and people just don't use metaphor or they don't want more explanation about the word.
What's inside doesn't matter. What's spoken cannot be taken.

It was not meant to be anyway.

There's someone who was eager to explain this answer and hoping that it will change my wrong perspective. And when that happened I remember this conversation had happen years ago. It's been a while but then :
"now I get it :)"