Trying to be still when I really want to scream!

[psalm46:10]

Hello,
This is my first post here, although I have been reading posts for the past couple months.
Let me start by giving the background:
My H and I have been married for 13 years, together 17. We have a D9 and a S who will be 8 in a couple weeks. I was 19 when we met, he was 25 and has 3 kids from his first marriage. We have been mostly happy throughout our M, going through minor problems along the way. About 5 years ago, I learned that H had an addiction to "adult chat sites." He was emailing thousands of women, met a few for lunch/dinner, but swore there was nothing physical (I'm not stupid). I chose to forgive, we went to counseling, and all seemed better. Two years ago his business went under due to the economy and all went downhill from there. He began detaching from myself and the kids- he had a new job, but it was working for someone else, and that was not "his dream." He would come home from work, grab a beer, and sit in front of the tv, barely speaking to anyone. About a year ago, I found out that he borrowed a large sum of money from his brother to try to keep the business open the year before. He lied about it until he couldn't lie anymore. We went to counseling again, and things seemed like they were improving. In April he began to act like a different person. He was working out every day- would get up at 5 am to workout before work. He was working later. He claimed it was because he was about to turn 44 and needed to take care of himself.
On 9/5, after returning from a family weekend at the beach, he told me that he "needed his space." He said that he didn't know himself anymore and felt that he had to move out in order to find himself. He moved into the spare bedroom and has been there ever since. He told me that he is going to counseling to work on his issues (terrible childhood, etc.) but that he does not want to be married anymore. He has cut off all communication with people from our church who care about him. He told me the other day that he wants me to come up with a "figure" that I need to live on so that he knows how much he has to get an apartment. I thought about it and told him that I would not help him leave. If he wanted to go, then he needed to do the work involved. Honestly it would probably be easier if he did leave, the tension would be gone- but that is not what I want.
I am in counseling, dealing with the issuses I have that led to this situation. I read DR, along with numerous other books. I am keeing busy with activities- I started running in the evening to give him time alone with the kids, and to allow me to clear my head.
I truly believe he is going through a mid-life crisis, and I know I just have to be patient, but some days that is just so hard! I am trying to be still, knowing that God is trying to teach me lessons through this process, but again, that is easier some days than others. Any advice? Thanks for letting me share!