In Dear Sister (Grand Central, Jan.), Horton recounts advocating for her sister, Nikki Addimando, after Addimando was charged with killing her abusive boyfriend in 2017.

In the book, you discuss missing the “red flags of domestic violence waving in front of your face,” despite your close relationship with your sister. Why do you think so many people find themselves in similar situations?

I think a lot of it is human nature. Sometimes, the closer you are to something, you can’t see the full picture. You just can’t wrap your head around the idea that something like this could happen to someone you love. If you don’t have all the information, your brain naturally fills in the blanks with your own story. I think that’s something I carry with me to this day—that you actually can’t really know even the people in your own house. It’s a little frightening to think about. I keep my eyes open a bit more than I used to.

What have your sister’s experiences, and your advocacy on her behalf, taught you about the ways the U.S. handles domestic violence?

I don’t know that prison is the way to hold abusers accountable. I think we need to imagine a new way to handle this, because we live in a country where nearly three women are killed every single day because of intimate partner violence. The vast majority of our women prisoners are survivors of violence. I think if it was a simple matter of a couple of new bills, we would have done it already. From my perspective, it’s going to require an entire system change, quite frankly. I think that we need to take this seriously, and look at it as an epidemic.

After Nikki’s arrest, you took over caring for her two young children, which your own son, Noah, came to resent. How did Noah feel about you sharing his feelings that he was “left behind” in the book?

I think he felt seen. I’ve tried to create an environment where he can be truthful, even if it’s about something that he thinks I’m not going to like. That’s something that our family does not do well. There’s a sense of, “Just tell me the thing I want to hear, because I don’t want to have to feel anything uncomfortable.” So I was really proud of him for saying that, and when I was writing the book, I brought it up. When I discussed including it, he said, “Yeah, I still think that.” He’s so smart that he does think, “Yes, my mom did the right thing, and yes, I really needed her.” His dad had disappeared, his grandma died, his cousins, who were super annoying, were in his space, and he needed to be chosen. And he recognized that I couldn’t do that. There’s a cost to everything, and, unfortunately, that was a cost. I’m hoping that when he’s grown, he can process it, and maybe he will change his mind.