What is the best way to tell a child that his parents are going to separate?

This is one of the hardest dicussions I ever had to with my sons, they were still young when my wife left and didn't reallyy understand it untill they were much older, I just sat them down and explained the situation to them and answered any questions I could for them and tried to be around for them more often.

You must be completely honest!!!!! No matter how young they are. I don't know how old your child is, but when I separated from my wife my son was 4 and my daughter 7. I took them out for the day and explained the situation, you must make it very very clear that the child is in no wat at fault. Do not allow your personal grievences with your ex to come into the conversation and do not ever say anything bad of his/her mother as no matter what you do she will always be the mum. just make it clear that no matter what Daddy will always be there for them.