I am so sorry to read your situation. I can't offer advice, since I'm relatively new to this, but I can offer my empathy for the extreme pain your are in right now. I truly understand. There is no pain like this.
I can also tell you that although your situation feels hopeless, I honestly believe (after reading many similar situations) that your husband is conflicted and may eventually come to his senses. You have time, please don't panic. Even divorce is not truly "the end". (I read that 14% of couples who divorce eventually remarry one another - a figure that astounded me.) I am in a much more dire situation. I was in a 19 1/2 year committed domestic partnership when my beloved partner said he "didn't love me enough" and ended it. Three days later he met a woman on the internet and now - less than THREE MONTHS (!) later - he has purchased her a new house and is planning on marrying her.
Like my partner, it seems that your husband has seemingly changed over night, he is no longer the responsible, decent, family man you knew, and he is determined to go on some slash and burn midlife quest that he legitimizes as a 'ministry'. To him, doing what he wants is the only thing that matters right now...the feelings of others, and "right and wrong" no longer figure in his daily decisions.
You are not wrong to try so hard! Believe me, if you didn't try with all of your heart, someday you very well might regret it. Listen to your lawyer, lawyers see hundreds of divorces in their careers and they know how estranged couples behave. Your husband truly does seem to be conflicted/confused. Trying is the righteous thing to do.
Sometimes I question the righteousness of my small hope in my partner. I have never interfered with his new relationship, but I refuse to display anger, resentment, or any other behaviors that would further alienate him from me and push him closer to the OW. I act as a friend - because he was my BEST FRIEND for nearly 20 years. Can you keep up a friendship with your husband even though he doesn't deserve it right now?
Me: 35 Him: 43 Together: 19 1/2 years 1st Bomb (IDLYAM): March 2011 2nd Bomb (OW): April 2011 He abandons home/bills/everything: May 2011 He's bought a new house for OW: September 2011