Bill and Hillary Clinton share a long history and a daughter. Both are intelligent, well-educated individuals that respect those aspects in each other. I believe, weathering the embarrassing turn of events in Bill Clinton's public affair while serving as President and his consequential impeachment, left Hillary publically betrayed and personally humiliated.
Living apart now, experiencing her own personal political success, pride in their adult, successful daughter and Bill's ability to regain his bearings on a personal and professional level, has revitalized a deep respect and friendship between these two former spouses. The public demeanors they portray when seen together is one of two civilized, intelligent people that remain friends with many fond memories of a shared past together.
As they grow older, it appears they make better friends than bed fellows. They set an exemplary example of ex-spouses with a first-class acceptance of each other, the ability to agree to disagree, still be able to laugh with each other and remain positive about a future that will probably always include each other as close friends..