When I saw your post I felt similarly to 25. Reading your response to her and 25's to you has prevented me from taking an action I would have regretted in response to two awful things my H did to me today.
I too have been in this 7 years. My H has also spoken of a time in the future when he will have a utopian relationship with my children when I am not in the picture.
As much I want to hurt this man, and I do, I can't hurt my children. There is a poster on another board I follow who bravely confessed that her child has not spoken to her in 3 years because of how she handled her husband's infidelity and departure. Please understand that I am in no way accusing you of that and think you are an exemplary dad. But, it gets me thinking about my own behavior and what there is to gain from venting, responding, whatever you want to call it. Even if I am not doing anything to the children that would jeopardize his relationship with them, what if I am doing something to him that keeps him away from that relationship and in turn harms my children.
Regardless of whether she deserved it or not, she does not deserve your energy, your passion, your heartache, your supply, whatever one can call it. This woman is mentally ill. No sane mother would do as she has done. Men do this stuff every day. Women do not. Not in the same numbers.
I hope that you can find it in your heart to forgive her, to step out of the middle as 25 suggests, and to let her deal with the fallout from her own choices. There are too many proms, dates, weddings, graduations, breakups, celebrations, and disappointments that require your attention for your beautiful girls. Don't give that energy to her. If they are 30 when it happens, they will better be able to navigate their feelings and process the choices she made and did not make, and better positioned to evaluate the lives that you created for them instead.