Not as bad as all that
It's not a good movie by any stretch of the imagination. The writing left a lot to be desired and the acting was mediocre (except the guy playing Christian, he was downright bad).
Next are spoilers:
Nevertheless, I truly liked the ending, the way she responded after the lashing seemed entirely genuine and justified to me. I liked that she put her foot down and wouldn't allow him to bully or domineer her into staying, despite loving him. Obviously I haven't read the books, so I have no idea how she ends up back with him, but I kinda wish they left this one as a stand alone, instead of coming up with a contrived reason to make a sequel, be it a novel or a movie.
As long as there are slaughterhouses, there will be battlefields.
-Leo Tolstoy