Glenna, this is so honest. I feel for you, but have no answers and wouldn’t even try. I’m not you. Do your older children know you’ve been writing this book? What if you asked them what they thought about you writing about your life — which of course means their lives, too? What if you asked all three of them? If they beg you not to do it, you’ll have your answer. If two out of the three say go ahead, it’s that third one whose feelings you’ll have to consider.
Have you thought that maybe the writing itself was cathartic enough and it doesn’t need to be published in order to have done what you asked of it? I understand your wish to help others, but, as you said yourself, family comes first.
You might hold off and wait until your children are older. Or you might write under a pseudonym, changing the names in the story.
Whatever you decide, it’s you who has to feel comfortable with your decision. Take your time and think it through. Good luck!