No but it is implied heavily (with voices heard to match) in whispers in flashbacks for our main character. Nothing is SEEN on screen, but you can HEAR the implications of it in her mind/whispers.
Not sure WHY someone said yes but there is literally zero sexual content in this film. Only them flirting heavily, but they never go past even kissing. Not even heavy petting. Just. Hugging. And Kissing.
No one was possessed in technical terms. It appears that a ghost/devil/whatever is whispering in our main characters' ears and manipulating their decisions through doubt. But no actual possession occurs.