transformation Power Struggle

I have been wanting to play more with power and gender dynamics, so came up with this scenario. I'm equally happy with either role, so you can pick your preference!

Set in a time or place where women are still considered property of their husband (early 1800s, medieval, or a fictional world would all make fine options). The female character is a rebelliously ambitious and independent spirit,  recently forced through an arranged marriage to wed her childhood friend (male character), who makes it clear he expects her to fulfill her proper role after their union. Unsatisfied and frustrated,  the bride turns to witchcraft,  conducting a special ritual of fertility before the night of their honeymoon. 

While the exact details can be worked out and negotiated, I imagine the story as a sensual power struggle, both newlyweds trying to dominate the other. If she dominates him, the ritual allows her to reverse their roles, transforming her into either a man or futa (your preference) and him into a submissive woman. If she fails, and submits to him, the ritual reinforces those roles instead, and she will become his hopelessly submissive housewife forevermore. 

 Open to any twists or alternative ideas as well, just message me your concept!