“I put you high up in the sky
And now, you're not coming down”

Miley Cyrus – Wrecking Ball Lyrics on LyricsMode
Liam is obviously more famous because of his relationship with her. He's gone on to star in blockbuster movies ever since they started dating. Now she's telling him he's a big-headed douche who needs to hop of cloud 9.
She put him high in the sky, (above her) she made him more famous after there dating and when he got more fame he never went back.