Why the Battered Woman Stays with the Brute

I’ve written a novel with a battered wife for a supporting character. Given the recent noise on domestic violence, it seemed appropriate to share the conversation I had with myself that led to my creating a fictional persona that an audience would believe. Who is she? She’s the mother of our main character. Not a main character herself? No. but she’s important to the story. So you don’t have much time to present her in a way that makes sense to the audience. Exactly. Married? Separated. Why?