A betrayal of whom? Him? Do you seriously think he won't seek legal advice if things progress to divorce? Of course he will. And he'll be more than glad to pay for it if he thinks it's to his advantage. You are betraying NO ONE by seeking information. You will be betraying yourself if you don't!
Yes, Mums can be old fashioned. My mum was shocked when I filed for divorce because 'marriage is forever'. But she was supportive even if she didn't agree at first. But my case was different, I instigated the divorce because my ex was abusive and announced (after we had been married a few years) that he never wanted children. But my point is, once your mum understands that your husband doesn't want to 'sort things out', she'll come round. And you don't have to explain that one of the issues is that you aren't 'taking care' of him. That's none of her business and an idea that went out (or should have ) with the bustle!!!
I'm glad you're seeing a counselor. I had more than a few session way back when where all I did was cry, too. That's fine, because that means you are in a supportive environment when you're there. What you want to aim to achieve is acceptance. Acceptance of who you are. Acceptance of what you are due as a person. Acceptance of what he wants, because if he won't at least try counseling it sounds very much to me as if his mind is made up.
You cannot change his mind. There are no magic words that will make him say "Oh what a fool I've been". (I've been there and done that. It doesn't ever work) Right now the important thing is to seek help (legal and emotional), to find acceptance of his decision, and to behave with dignity and grace.
So, now, no crying in front of him. No begging for chances or changes. Dignity and grace. And a good dose of self interest. You will be so glad you did.