Charlotte,
I didn't read your post enough to realize you are in a marriage of 24 years so let me continue my story.
I divorced my first husband after the 21 years of misery at the point I felt my daughter was ready for it. As a matter of fact, she and I sat down and talked about the situation and she told me she knew her father and I would divorce eventually. She recognized my unhappiness and wanted me to be happy. The fact I had her blessing made things easier for me but I was hell bent on getting out of the marriage at that point anyway.
I am now remarried to a wonderful guy. We have been married six years and they have been the best years of my life. I have traveled to Europe and other places several times (a dream of mine), I have been scuba diving several times (another dream fulfilled) and have completed my undergrad and Master's degree. I have finally moved forward and love my life now. My daughter loves her step Dad dearly and loves her like his own daughter.
Do I regret staying in my first marriage? No. For many reasons and one of them is because I learned so much about myself during those awful years.
I remember asking myself one day if I thought I could live that way another 21 years and the answer was "No". I raised my daughter as best I could and she was now on her own. I felt if I stayed with my ex any longer it would only kill my spirit.
Your boys will be fine. They may be angry for awhile until they adjust but at this point, it really is your life, isn't it?