How should you deal w/meeting the business partner? The same way you would in the office. You have your list of questions about the business and leave the conversation to nothing but business. You want this person to feel safe and willing to speak to you about the business in the future.
If he asks how you are doing, I would say okay. You do not need to go into detail w/this person about your personal life and/or what is going on in your marriage. He/she is nothing more than an employee and you don't own him/her an explanation of what is or isn't going on.
Be sure to thank this person meeting up w/you.
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.