The business partner may feel uncomfortable in responding back to you right now. People, in general, do not want to be in the middle of a marital situation, i.e., separation/divorce. In his mind, he could very well want to distance himself from you for the time being because your h may have painted his rewritten history picture to him. Also, he may think that you have an ulterior motive for asking for the info, i.e., to tell him about your situation or try to get info from him. From his non-response, I would suggest that you contact your accountant for info or have your lawyer request the info.
As for contact your h...be still and be patient. He's not ready to contact you or see the children. It takes time for them to work on themselves and a MLCer does not like to be pressured into doing something that they aren't ready to do. The best thing you can do is reassure your children that their father loves them. Only contact him if it's an emergency, but other than that...leave him alone.
I know that this is very difficult for you and the children, but the more you pursue him (calls, texts, emails, etc.), the more he's going to distance himself.
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.