Expectations of others will drive anyone batty and create anger and resentment. It takes a lot of energy to be angry and resent someone because they either didn't do or say what we had hoped.
When the BD, and still today, your h doesn't have it in him to help anyone but himself. He's not capable of taking care of you and ensuring that you are okay. I have a feeling that he knows that you are a very strong and independent woman who can take care of herself, but he doesn't realize that you still need someone to lean on once in a while. Your h sounds a lot like my xh who would come to the rescue of others, but when it came to doing things for me, it didn't happen and I did ask him about it one time...the answer...he knew I could take care of myself and anything that needed to be done. He didn't feel needed by me. I don't know if that is how your h feels about your situation, but maybe his "love language" is that he needs to be needed, affirmed and recognized for what he does. Maybe he's getting that from others at the moment.
Yes, the lady client is being way too friendly outside of a work relationship....but she knows that you two are separated and he's there by himself. She sees no harm in inviting him to games, but I also see this being more of an emotional affair at the moment. She sits there and offers him friendship, comfort and most likely encourages him to talk about himself, the business and life. You do not have a clue as to what he's told her about you. If she is encouraging him to divorce you, I think she has an ulterior motive in suggesting this, i.e., she wants him for herself. She's using every excuse she can find to have him be around her and yes, she is playing the damsel who can't take care of things for herself or hire someone else to do the work for her. Your h is fragile and vulnerable and doesn't have a clue that he is being manipulated by this client/so called friend. He needs to figure this out on his own and cut the after hours business w/this particular woman.
I will honestly say yes, she would pay for your h's lawyer to help him divorce you. She would do anything to have this man if he just said the word "yes, I need to divorce her".
Actually, I do not think what you posted about your h is petty. I've been there and know what you have dealt with and it's very frustrating when your spouse will go off on his white horse and rescue others, but leaves his spouse at home to deal w/things.
I hope the books will help you. Letting go of expectations is very freeing and it allows that anger, resentment and disappointment slowly disappear. We are fixers and because we hold ourselves to a certain standard, we tend to forget that others do not do the same. It took me a long time to learn to accept people for who they are and not expect them to do or act the way that I had hoped.
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.