It has been an intense and illuminating process for both of them. She had reached a point in the relationship where she had to decide between maintaining the status quo and avoiding dealing with issues, breaking up, or getting help.
One of the things that she has been so struck by is how, without having any awareness of it all, her deep issues/schemas/conditioning have meshed with his deep issues/schemas/conditioning in such intricate ways that have impacted the way they relate to each other.
This phenomenon is called the unconscious fit between couples. It comprises all of the things we are not aware of, but that still impact who we are and how we relate.
He, for example, had a role growing up in his family that revolved around catering to his demanding sibling. As a result, his MO has been to be passive and give too much so that he can maintain his role as a selfless victim. This passivity plays out in their relationship in a number of ways.
She grew up with a critical dad that ran hot and cold so that she was always feeling like she needed to do things to please him and to close the distance between them. She became aware that she has been doing something very similar with her boyfriend and also that the more safe and stable she feels in the relationship, the less excited she is. The old dance she had with her dad and the old dance he had with his sibling is very much alive in their relationship.
They are discovering all of this now. Even though it is difficult and painful, she feels like a huge weight has been lifted from her. All of this stuff impacts us whether we are aware of it or not. The less aware we are, the more likely it will negatively impact our relationships. Shedding light on it doesn't make it disappear. It just makes it possible to make connections and be aware when old dynamics are operating, so we can have more control over what happens next.
(All identifying information has been changed to maintain anonymity.)