Good for you! You are one smart cookie, and I am so happy to hear you have a place to go and a job.
That guilt you are feeling is not real. This is the result of 20 years of chipping away at your self-esteem. You're still a nice person, unlike him, and you might believe it is wrong to run out without warning him. But it is crucial that you don't tell him about your plans.
Please do not worry about him. He can take care of himself. This is his life that he created. He didn't take care of YOU and you must take care of yourself now.
Of course, if you are worried that he will come after you, take precautions to let your friend always know where you'll be and give her your family's phone numbers. Put the 911 on your cell phone's speed dial. Get in touch with the local abused women's organizations ahead of time so they will be acquainted with your situation.
You are doing the right thing. Be brave. Keep in touch.