I am in the same situation...

my kid will go to college next year, I am planing to buy a new house and live seperately with my wife. I knew she will not agree to divorce me and I don't want to go through the complicative processes. SO, the only choice left for me to to live seperately with her - but I will keep the marriage. My wife acts the same way as yours. She has her advantages and disadvantage. Just that I can only endure her disadvantages for the sake of my kids. One my kids are gone, I will live seperately with her.