Hello, I'd like to help you with your question.
It sounds like your husband is not listening to your concerns. You are right, he is going a bit further with this woman than is something you can be comfortable with. And the fact that you have noticed is important. What he is doing can lead to an emotional affair or even a physical one.
You were supportive of his business with this woman but now it has gone beyond business and you are noticing the signs of the behavior. He is having longer meetings than is necessary, he is spending a lot of money on her, and she is starting to cross over into your personal life, meeting your kids, relatives and even taking food off your husband's plate. Those things are not needed for your husband and her to make a business deal.
It would help to explain to your husband the reasons why you feel that his relationship with her has crossed over from business to personal. Let him know that while you support him having business dealings with anyone, you do not support anything personal. Make sure he is aware that you have noticed that he treats her differently than his other business contacts. And also say that there are less boundaries with this particular person, which can lead to misunderstandings about his intentions. Mention that although he may see this relationship as innocent, she may not.
Ask your husband to set boundaries with this woman. Even if he would lose her business, it is better than causing problems in your marriage. He must pick what is more important to him and what to make a priority.
If he is resistant to what you say and feel, then you might want to suggest seeing a therapist together. Sometimes a spouse who will not listen to concerns from their partner will listen when someone else points it out. If he will not go with you to therapy, go on your own. You need the support and a chance to talk out how you want to handle the situation.
Also, look into resources that can help you gain back your marriage, from your perspective and for your husband. Here are some to get you started:http://psychcentral.com/blog/archives/2009/04/11/12-ways-to-recover-from-an-emotional-affair/ http://suite101.com/article/how-emotional-cheating-starts-a32008
Chatting or Cheating: How to Detect Infidelity, Rebuild Love, and Affair-Proof Your Relationship by Sheri Meyers
Eyes Wide Open: Avoiding the Heartbreak of Emotional Promiscuity by Brienne Murk and Dr. Gary Chapman
I hope this has helped you,