From David Schnarch’s Passionate Marriage…
She detested how she hid in fear of [her husband, John's] disapproval and vowed to do things differently… she recognized that she’d never really feel “safe” if she couldn’t do it on her own.
Having made this momentous decision, Mary realized that she didn’t need “permission” to change herself or her marriage. It doesn’t “take two,” as the old saying goes. It takes two to keep your marriage the same; it only takes one to change it. When you change, the relationship changes.
She wanted to become sufficiently solid in her sense of herself that she would stop living in fear of John’s response.