Its totally your choice when to walk away. Only you know when to do that. I think you have been doing some great work on yourself with your IC. You have such great self awareness. But (IMO only!!) your IC is not making sense on her couples advice. So you are 100% responsible for you and yet 100% responsible for your H too? That is not logical. Accept full responsibilty for your 50% only.
All of us have parents that screw us up in some way, just as we will do for our kids. Its all part of life, I don't believe in the picket fence and apple pie family. Some of us get the hits in childhood. Some of us get the raw deals as adults. Some of us have to hold the marriage together early on. Some of us now. You did the best you could then, with the tools you could, just like your H is doing now.
My H was 100% ademant we were over when he said its over. It was what he believed ON THAT DAY. Just how logical is your H right now? He is in a deep fog and thinks this will be the answer to his problems. I don't know what he will do, but his anger has GOT to burn out. Maybe that last time he spoke to you was the beginning of the end of the anger phase? Maybe he needs this to move forward. Maybe he just thinks he needs it and if you stall and stretch out the process without making it obvious it will take enough pressure off him to keep moving through.
Look, you know your sitch best, and have a good feel for what you need to do inside you. It just sounds to me like the is your IC choice, right now. And also, surely the time to let him go is when you are letting him go with love, not with exhustion?
Hope I havn't confused you too much with my ramblings.