Divorce problems

My wife and I are divorcing and we have two young children, 7 and 9. We are going through mediation and I believe that we can approach this in a very civilized manner. We both also feel that after the divorce we will be able to work in the best interests of the kids. My question is, is it even necessary to use the term "divorce" when explaining this to the kids? They are smart kids so they may bring it up themselves. But that word carries an ominous tone that the kids may or may not understand. Would it be better to just say that we decided to live apart?