No judgment here. I've been in my own situation for 6 plus years and have stayed for my own reasons. But I believe each of us has a tipping point - it just depends on what yours is.
One thing that you may want to ask your self is - would you want (your life) for your children?
Although I knew in my heart of hearts that I deserved better and that I was not planning on living the rest of my life in my situation, how it was effecting my children is what helped me to make my decision sooner then later.