Sophiel - Your does appear to be having a life transition crisis. The fact that the affair is long distance sugests that it is a fantasy. The fast that you talk about the 'fog' is suggestive of a crisis.
Many of them cannot wait to start divorce proceedings - they feel it will bring them clarity. They are confused. In your h's case there is already a lot of confusion around.
Do you want your marriage - this one, as opposed to being married? If you do, then it is worth fighting for. There are wiser [and more successful] heads than mine here. Visit BND's thread, for example, and ask her to check your sitch out. I know she will. She successfully reconciled, but it took a long tme. Her h left and went to live several thousand miles away!