What surprising item was found in Olga’s room?

While lying awake in Olga’s bed, Julia notices a post-it in the pillow. Written on it is the name of a prescription, along with the words “I love you.”

Curious, Julia ventures into Olga’s closet to snoop for more clues. In the closet, she finds lingerie and a hotel room key. This deeply confuses Julia, as it is in strong contrast to her previously-held conceptions of Olga.