A few years back I started watching this movie, but fell asleep half way through and have always wanted to see it in it's entirety. I believe it was french. It was about this girl who lived with her boyfriend, but for some strange reason she had trouble having sex with him. She would have sex with anybody else though, in any place. I remember one scene where she was outside a stairwell having sex (not with her boyfriend), and another scene where she allowed a man to tie her up in a hotel room. Any help in identifying this movie for me would help

It sure sounds like Belle de jour, but I don't remember the stairwell scene, and she's married in that one.