It was necessary to respond when she said how she had treated you. If that's all she said, it's not enough. It's not an apology, and I seriously doubt remorse, yet. Even if she had a twinge of remorse, it isn't worth a dime if she continues contacting OM. Her words are worthless until her behavior begins matching what she says.
BTW, whenever we point something out, you don't have to approach her with another apology. We are just trying to help you learn as you tell us the daily development.
Have you read any threads about the WW mindset?
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!