Friends with an Ex?

Can you be friends with your ex? For many the idea is completely out of the question. However, for some people before they were married they were friends and they want to keep the relationship. What happens when one has hopes of rekindling the romance? It may not be healthy for either former spouse. http://www.bostonglobe.com/lifestyle/2014/02/21/friendship-after-divorce/N4L31FZilMt50sMB8TGaYN/story.html