I'm glad you got upset about your husband communicating with your best friend. In theory it sounds okay.. someone who knows you so well trying to coach and advise your spouse on how to reach you. But.. it puts her in the middle.. in the middle of you and your spouse working out issues directly. And although both you and your spouse benefit from snippets, it's keeping you and your husband from truly growing.
It's Maria time.
Fix Maria first. If you broke your arm would you set it yourself? Uhh.. I think I'd go to a doctor and have it tended so it heals perfectly. After all, they're the professionals.
It's the same with emotional issues. Most folks can get through things after a fashion. But using a professional (individual counselor) gives you the tools to heal swifter with better results in the short and long term.
Once there was a woman with an overflowing basket of bread which she offered to a circle of friends. Each time it went around, she refused her share and kept giving to everyone. As time went on, others were filled as the woman became gaunt. Now she was the one her friends were concerned about, but this woman refused even a single crumb. Imagine her surprise one day to find herself too weak to hold the basket yet too proud to accept what she always offered. Caring, giving, love.
My dear loving friend. Take care of you. You're so blessedly worth it.