I am mother of two toddlers and going through a terrible divorce. How do I explain my children?

I have a close friend who divorced with her husband when her kid was 4 years old. It does affect the child because he will ask where is his daddy. However, the mother showers the kid with a lot of loves within the tough period after divorce, plus with the full supports and loves from the grandparents, he is still a happy child. When kids get older, it is unavoidable people around them will ask where is his daddy. Do not avoid but to teach the child to accept. Reading up story books relating to divorce will help them to relate better.