I have always liked slightly messed up love stories. My favorite books and movies are Vertigo, Gone with the Wind, Great Expectations, 1984, and Atonement. There are elements of these works in my book.
In Life, I knew that Jack and Christine were messed up people. They are deeply in love, but they don't know how to be in love. Jack wants her to love him completely. Christine likes leading him on. It creates passion in him and causes him to lose his self-control. She enjoys driving him crazy because she knows that he truly loves her. If he didn't love her, she wouldn't be able to get him so upset.
I think there is also a fatalistic view to their relationship as well. They both know that this can't last. Jack is going to become a famous comedian. Jack won't be able to go off and do what he needs to do if he is tied down with Christine. It's not fair to her. Is he going to choose his career or her? Which does he love more? They know they both have to make a choice. Jack tends to look to the future. Christine just wants tonight and whatever time she has with him.
As a writer and a reader, I like to see how people are going to deal with important decisions in their life. It is in these life changing decisions that we really get to know a character. Will they regret it? Will they change their mind? Or will they live with their decision for the rest of their life?