Wonderingwhy, Angel gave you a lot of sound advice, follow it. Your reason for staying may or may not have anything to do with your abandonment as a child. You really did go through hell as a child and I'm sorry you had to suffer that. I can't even imagine what that must have been like for you to lose not only your mother, but basically you lost your father as well. I hope your grandparents were good to you.
I think that possibly one of the reasons you've stayed as long as you have is the fact that you lost one man in your life for several years and didn't want to risk having to lose another one. But, that was then, and this is now. I think the only reason you are staying now is fear of the unknown. It is much easier to stay in a situation where you are familiar with the surroundings, bad as they may be, then to venture out into the unknown where things are different, unfamiliar, and sometimes frightening. But if you are as miserable as you say, then you are wasting what little of your life you have left to know happiness again. Sometimes you just have to take a chance and go for it. I did, and I've never regretted it for one minute. The only regret I have, is that I didn't leave sooner. I didn't have any abandonment issues to deal with, and I still stayed for most of the same reasons you have. NO.1 I did not want my children to grow up without a father around. (He was around very little and when he was he paid very little attention to them, BUT, he was still around.) I cultivated my own activities and friends. I was technically married, but more single. I put up with it for 20 years, (I can't even imagine 35!)
Like you I loved my husband too, when we got married, and planned to spend the rest of my life with him. But people change, and generally not for the better, and as they get worse you keep hoping they'll change back and things will be the way they used to be in the beginning, but they never do. And then you have to make a decision, do you want to remain in a stale, stagnant marriage, or do you want to open the door and walk out and breathe in the fresh air. It's a decision only you can make. At this point it is only a matter of how much more do you, or can you tolerate. I realize you have been married for over half of your life, so was I, and the thought of starting over again and being alone was rather scary at first. I didn't really know if I could do it, but as the months went on I became more and more accustomed to my single life, and before long I was luxuriating in it. The longer I was alone the more I liked being alone. That was years ago and I am still alone, (well not quite, I have two wonderful dogs that are the best companions in the world) and still loving it!!
I've had several opportunities to get married again, turned them all down flat. I so love my single life I wouldn't give it up for anything, not now or ever. I even lived with a guy for a year (only 1!) and that took care of any future notions of EVER getting married again. So don't think being alone is such a bad thing, sometimes it can be the greatest thing in the world.
Stay involved with the things you love doing, your children, grandchildren, family and friends, and if you do decide to leave the old goat you won't even miss him!
And don't feel sorry for him, I went through that one too. He even threatened to commit suicide a couple of times, if I wouldn't take him back. That lasted for about a year and a half, that was several years ago and he's still alive. So don't feel guility or sorry, just do what is best for you. Like I've told others, you only have one life to live, it's now or never, you blow this life, you don't get a second chance at it. This is all you get, what you do with it is your choice.
Good luck making the right decision, for you!