My wife did exactly the same thing after 19 years. Just want to be on her own. Very focussed, wants to party and "go on" with her life. Three teenage children. She moved out and is staying on her own very confused and apparantly crying a lot. It has been two months now and she hasn't started actual divorce proceedings because "she is too busy". I am moving on with my life as before and have done a lot of soul searching but also realised there was not much I could do differently and at the moment I act "normal" towards her.
My biggest concerns with a divorce under these circumstances are:
1. We have children and build a family life because that is how we are wired. This family life eventually extends when the children are getting married and have children of their own. I believe that that is most gratifying when a husband and a wife are still together as a family at that point in life.
2. Children likes to come home to their parents. There is no better feeling than when your own mother and father are still together.
3. To be alone because you have chosen to break up your own family for selfish reasons must be a bitter pill to swallow.