Though I did not have children involved, my situation was similar. I was scared to leave, scared of all the things he threatened to do and scared of all the things I knew he would likely do.
I wanted it to work and I am sure most of us that have left did but after 15 years of the same thing over and over I grew tired and had to face the fact that he it was unlikely he was going to change but I was.... I was getting weak, sick, depressed and weary.
I followed the wonderful advise from others here, though I had been journaling since his first rehab, I started preparing myself, by documenting everything, reported his threats to the police, started setting money aside, packed an emergency bag, removed things I couldn't replace, confided in people I could trust for help if I did have to leave quickly and most important as soon as I knew I was leaving I went to see an attorney to get legal advice.
You know him better than anyone, if you think he will raise a stink, he probably will, most of them do. Should you decide to end it, the more plans you make in advance the easier it will be for you and your children and you will already be several steps ahead of him.