Dbing is actually for you...it helps you to find your footing during the crisis. Your h has entered the MLC tunnel and nothing will turn him back until his crisis is done. However, the changes you have been making must be for you and not to try to make him change his mind. The changes must become permanent and very real. Are you happy w/the changes that you have done thus far for you? If so, please do not revert back to your old self.
If he brings up the subject divorce, some have said that they need some time to adjust to the idea, others change the subject and hope that it will create a change in the person's thinking during the moment. The words separation and divorce are often used as control measures when we get too close for their comfort. As for him being done, yes, he's done because he's depressed and he doesn't have any feelings for you or the situation right now. In fact, he's searching for something that will make him happy once again....unfortunately, happiness coms from within. He's discover this along the way, but not for a long time to come.
I would strongly suggest that you start moving funds to a new account, removing your name off joint accounts, etc. Your man has entered the twilight zone and spending will be one of the major self medications along the way.
As for the third time a charm...well houses built on sand will eventually crack. The less you say to him about her the better. Why? Because, in his mind, he has to defend her from you and others who may frown upon the relationship.
It's time to start focusing on you, your finances, and family. I'm very sorry you are here, but this journey that he's taking will be a long one. You are on the coaster ride from h@ll. Buckle up!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.