It makes her a three-dimensional character and provides
suspense; we don't know if she will stay with Christian. It makes her
sympathetic. We feel for her dilemma. She's crazy about him, but he's just
plain old crazy (unless you’re a fan of sadomasochism).
Thus, in real life we may prefer partners who are relatively
drama free, but this would make for very boring literature. When you are
developing your characters, make sure they have enough conflict, both
internally, within themselves, and externally with other people.
Sigrid Macdonald is the author of three books, including Be Your Own Editor, and two erotic short
stories, which she wrote under the pen name Tiffanie Good. Silver Publishing
just released "The Pink Triangle," a tale of friendship, lust, and
betrayal. You can view her story here: http://tinyurl.com/6v65rgr