Did I Miss Something?

After watching this recently, I found myself asking more questions...who was the man who Marion left the restaurant with so abruptly on the night of the cast dinner given by the director? Several more times there were fleeing glimpses of him, and a glance between them, but I never saw their real connection. Ditto the attractive, slender dark-haired woman who steals possessions from the actors and is then seen in the Gestaopo HQ where she and Marion stare at each other.
I was also unclear as to who loved whom..Marion is seen several times beginning a love scene with here husband, also with Gerard D, then, we are left to assume, with the strange man (noted above)with whom she apparently apent the night (recall that the maid comes in with breakfast and the bed has not been slept in).
Much like other movies that effect a 'play within a play' I wondered at exactly what point reality separated from the play. Certainly the last scenes are initially taken as current day reality, then the play ends...but was there artistic liberty wherein earlier parts of the movie were also part of the play?
Overall, I felt cheated somehow as I left this movie with more questions than answers, and the last scent makes one feel manipulated. (Other posters have noted this). Finally, I tried to empathize with Marion, but was she a loving wife struggling under so much adversity or one rather indiscreet..her love adventures seeemed not infrequent.