Mila, you are going through the normal stages of loss and grief. You are not, I suspect, truly detached, but have wisely detached your feelings from the situation. A therapist friend ponted out to me that I did that to protect myself - which I found a good insight.
I agree with the other posters. You have to talk to your h about his behaviour as a business partner. If he wasn't your h and was another business partner - a woman friend for example, who was treating you like this, you would sit down and talk about it, if necessary with a mediator. It is a sign of your husband's sense of guilt and MLC entitlement that he does not tell you he is going away.
You need to separate as much of your finances as possible. [I speak from experience, should have done it sooner myself] Talk to a lawyer and also a professional bsiness adviser about the situation while you h is away. I don't know the legal structure of your business. Can you being in someone else to help boost the business, or buy your h out if he isn't pulling his weight. You cannot change his MLC behaviou with regard to the marriage, but as a work colleague you have every legal right to expect him to behave properly
Finally I agree with the poster who said if we can't be on our own why would anyone else want to be with us? Of course you miss what you had, but that has to go and be mourned before you can really start anything fresh.
You are clearly a remarkable woman, and will be fine.