My heart goes out to you man. I had my fair share of dry drunks during my marriage. After eleven months sober, in the program, working the steps, things go bad in the marriage. In my case it was because she was having an affair. Do not do what I did. I had a three day slip. I did however get back to the rooms and have 19 months sober.
I do hear a lot about people going through divorces after they get into the program. I've heard several reasons why, but one I hear more than any other. Control - most alcoholics are like another kid for their spouse to take care of, which gives them a lot of control in the day to day family decisions. Once we become more involved the fear of the loss of control hits them. While some are happy to finally have help with the family, others do not want to give up that control so they find a way out. That is what my ex did, and she used another man to do it.
So stay sober, be there for your children, and remember we are powerless over people too.
My ex did try to alienate me from my kids and move them away. She not only failed, but I share a closeness with my kids that I never have before. This would not be so if I were not actively involved in the program.
Good luck I hope things turn out for you.