Dirty Work (2018)

Arabella, a struggling fashion designer takes on a job working as a personal shopper for Marylin- a successful erotic novelist. One day, Arabella is sneakily trying on some of Marilyn's expensive garments, when Marylin unexpectedly comes home early......but she is not alone. Arabella hides and watches as Marilyn enters with an attractive man who is not her husband. The pair make love on the bed and Arabella is turned on by what she sees. Arabella continues to hide and watches Marilyn's many affairs take place in the bedroom, until one day she is caught by Marilyn who admits that she knew Arabella had been watching the whole time. Things get steamy between the pair, but soon they will be confronted by someone who knows about their affair and will do anything to stop it.

Source: TMDb