This is a song about a woman who is being reminded by a friend or counselor that if the person they love is continually abusing them verbally then that person doesn’t love them at all. ‘No one should cut your heart wide open” or “leave you broken”. The narrator in the song advises them to accept the hurt but to “walk off” and move on with their life because over time they’ll forget the pain. They also realize the person may want to “look in the door”, meaning to try to understand or accept some responsibility for their partner’s abuse. But that is futile. So walk off and let it go.
I’ve known a few men and women in my time and have seen what abusive personality disorders can do to their families. If you or someone you know is in need of help go here for answers: https://www.crisistextline.org/topics/emotional-abuse/#what-is-emotional-abuse-1