Mrs. H is right. Your darling kids will miss you terribly. You are irreplacable. In addition, you have virtues. You have stood by your marriage. Your H has not. Your kids will piece it all together. Comfort them. You may seek guidance from their school counselor too.
I feel deeply for what you're facing. In the not so distant future, you'll see the silver lining.
Please take care of yourself. Keep the GAL up. In these times, depression can slither in!