Schwarzenegger, Shriver separating after 25 years

So many celebrity divorce and separations this year but I'm most surprised at these two, I mean how can a marriage of 25 years that has withstand so many ups and downs just collapse.

They both released to the media

"This has been a time of great personal and professional transition for each of us. After a great deal of thought, reflection, discussion and prayer, we came to this decision together. At this time, we are living apart while we work on the future of our relationship.
We are continuing to parent our four children together. They are the light and the center of both of our lives. We consider this a private matter and neither we nor any of our friends or family will have further comment. We ask for compassion and respect from the media and the public."