L.B.
I am very sorry for you and what you are going through. Not sure if I am in any place to give advice, but here is how my situation turned out. My husband was having an affair when I was pregnant with our second son. We separated when my oldest was 4, youngest 3 months. It was a very difficult decision, but I simply could not take it any more, I felt it was the best thing for my sanity. Until I made that decision, I felt I was in limbo, crying all the time, and I'm sure my kids felt it through me. We had also gone to counseling. It was the counselor who convinced me it was time to get off the fence and make a decision. Several months after separating, he broke off his affair with his coworker, and at that time started persuing me again. We agreed to give things another try, after 10 months of separation. Against the couselor's guidance, he moved back in immediately. Well, low and behold, it only lasted 3 months, then another 4 months for him to find another place to live. When he moved out the second time, I felt so much peace, I was confident that I had done everything to make things work, but it was clear that it wasn't meant to be. I had finally taken charge of my future and happiness.
The divorce process took two years, because of our house, which I kept, and kids schedules. Although I was fully comfortable with my decision, in the process, my then 6 year old was a mess. He went from outgoing to withdrawn, would not communicate, had difficulty in school, we even had to hold him back in first grade. He then began seeing a counselor himself, for about 3 years. All through elementary school, I feel that he struggled emotionally. When he was 10, I remarried, and he still had a hard time. By the time he was to attend HS, I made the decision to let him move in with his dad and attend HS in the south bay. At the time I lived in SF and was not happy with the choices of HS. He will just begin his Sophmore year now, and finally, I see many changes in his personality. Being with his father and getting that attention is truely what he always wanted, and now I feel he is finally happy. So it took him 10 years but he is finally in a place where he has self confidence and self respect. Our younger son, I feel, was simply too young to ever experience his father and I being together, so he has never really been adversely affected. Us being apart is really all he ever knew.
There was a program we attended when the children were 7 and 3, called Kids Turn. As parents, we were separated in different groups, and the children were separated based on age as well. We all learned how to parent together but live separately, and the kids learned that it was ok to feel sad and know that there were many other families with children like them.
Good luck with your decision. I hope that you can get something out of my story that will help you in making your choices.