She wants to train him, to parent him. She shields him from family problems and indulges his moods, lest he either break down or blow up. The only relationship in which the woman rightfully exerts leadership over the man is as his mother. Whenever she begins to lead, she inevitably attempts to parent him. But there is a difference between being the helper of a man and the mother of a boy.
Fear often prevents reformation within a marriage.
The summons to Biblical obedience confronts the couple as a rather scary prospect. But she can fear his inept exercise of headship. She might even want to be led, but she is afraid that his incompetence will expose her to harm. She feels unprotected, exposed, vulnerable. Her fear can cause her to try to take over his leadership as she discovers that perhaps she can get the job done better than him.