Glenna that was so raw and honest! You definitely cannot destroy your manuscript. I am sure it will be a beautiful treasure trove of wisdom and life lessons. Sure there will be parts in there that are dark and painful. But I think it is great for your kids to see that side of life. Life is not all rainbows and happiness.
I believe we should share our failures with our kids and not just our successes. They will learn more from that. They will see how you faced your struggles and overcame it all.
Yes, I agree writing about their father and your marriage is tricky. Kids are always protective over their parents.
If you have doubts about it hurting your kids, you can wait till your kids are older and more mature. Once they have read it and are okay with it, you can publish it.
You are a great mom and a gifted writer too! The world should read your memoir! All the best!