Do I stay?

Let me give you a bit of background... For the last 10 years I was diagnosed with an auto immune disease that attacks my body and when I have a flare up I am bedridden in total weakness until it passes and then I recoup and am "good to go" with my daily routines. But I am no where close strength wise like I use to be.  My illness did not allow for full intimacy during flare ups. But as the years went on my husband and I separated emotionally and physically till it became two people coexisting in a house. He felt my job came before him and the children and my duty was to serve them BEFORE my job duties. If they conflicted I was to put he and the children first and the job last. Then, I found out after 20+ years of marriage that for one year my Christian husband had an affair and then I later found out he was addicted to porn for many years. Our children caught him on the computer before I knew, then I found out. At first he said that had I have given him sexually what he wanted he never would have gotten into porn or had the affair. I was in shock and it took me days to really believe it was true. He and I lost every position in the church because of his addictions which I guess is good so that I can concentrate on what is happening in our lives and deal with it , and my husband's response was... "so..." BUT after many years of service in the church I have lost all desire to serve in the church- I sought help with counseling and my husband went for awhile, then I saw arrogance and anger increase in his life like I had never seen before. Eventually I asked him to move out because there was no change. After more than 1 year he realized he needed help and sought it. He eventually asked for forgiveness and I saw some humility and change. But it did not last. After 1 more year of ups and downs, a bit of success and then failure I have lost hope. I NEVER believed in divorce, especially as a Christian, but I cannot handle the lies and ups and downs of hope and then being let down. I have gotten stronger in my self confidence, my role as a mother, and even a wife. I will not be walked over as I was in the past and have set boundaries that I believe God would have me set up. I have accountability in regard to my actions, responses and attitude towards my husband to my pastor and a friend. Even having been through all of this I still struggle with divorce and am sick to my stomach each time I meet with the lawyer. Deep down I still want the marriage to work, but reality says...look at the pattern...it is the same. I can no longer deal with the depression and sadness that has taken hold because my heart has been broken time and time again. I have run out of ways to help him, support or believe in him. I do believe he wants healing- but only God can do that for him. I do not know if I should sign the final divorce papers or just stay separated and continue to pray for restoration. My head and heart are in two separate locations. I know there is no black and white answer...or is there???