You can focus on the emotional aspects of their relationship, like how she is submissive in terms of respecting her partner's decisions, being supportive in family matters, and showing loyalty. For example, you could write about how she always defers to her husband's ideas about home decor because she trusts his taste, and in return, he values her input on other aspects of their life.
A story could revolve around the submissive wife's role in handling family disputes. She might be submissive in the sense that she always tries to keep the peace. For instance, when there are arguments between family members, she listens patiently to everyone's side, offers gentle advice, and is willing to take on extra tasks to ease the tension. This kind of submissive nature is based on love and family values, not sexual or erotic concepts.
One way is to depict the submissive wife in a story about her self - less acts. Maybe she gives up her own career opportunities to support her husband's dreams. It could be about her following her husband to a new city for his job and then building a new life there. This shows her submissiveness in a non - sexual and non - erotic way, highlighting her sacrifice and commitment in the relationship.