mama, i am so sorry for you and your little ones. (i knew you would be a wreck, but i was HOPING!)
i know how hard it has been for us and my oldest was only 4 last month. 7 is pretty old, but still way too young to understand. TRY, TRY, TRY to think about things that can pull you through, like "children would rather be in a split-parent life than a dysfunctional home" or "my family isn't broken - i fixed it when i got a divorce!"
and cry on the shoulders of the mamas on this forum because they can be some pretty amazing women when you need them!