OP reading through your thread, there are a few things that stand out to me (apart from the excellent advice you've already been given).
He claims they didn't 'do it' as he was so drunk he couldn't get it up even after much encouragement. Why would he lie about that - surely that's too embarrassing to admit to??
Firstly, this shows that he intended to have sex, the fact that he couldn't penetrate makes no difference does it? If he could, he would have. The fact that he thinks this makes it sound better just shows what little regard he has for your intellect. He is calling you a fool.
I get that the cheater has to take responsibility ( H is), make amends if possible (H is trying) and start to behave better in the future (can't say yet)
He is not taking responsibility. He is still lying to you. Even your counsellor told you you would never get the truth out of him.
He is not trying to make amends. Making amends would involve being completely truthful and not showing impatience or annoyance at your feelings.
Behaving better in future? Well we are now in what was the future and how is he behaving towards you. It seems that he is still trying to lay blame on you. He is getting fed up with you, after just 2 months, going on about it. He doesn't seem to really accept that he has to change.
He is (other than his infidelity!) a good man - always there for me and the DC, very hands on dad and helpful husband around the home
Actually, he is behaving the same way his father did. And you are behaving like his mother. So the two of you are doing exactly the same thing that caused him to need therapy. That is what kind of a dad he is.
it's been a horrific rollercoaster here and I've been vile so I'm not sure I've made it that easy for him. He could have walked so far but he's stuck with it
No, no, no, no, no!!! You have got this all the wrong way round. He has been vile to you. Did you cheat on him? Did you lie and shag around? Oh no, wait, that was him. All you did OP was express your hurt and anger, which you have every right to do.
You do not have to make anything easy for him. That is not your responsibility. He should be doing absolutely everything within his power to make life more bearable for you right now and continuing to support you over however many years it takes - forever probably.
He could have walked? He is lucky that you haven't walked yet. As soon as you are able to manage on your own, you should ask him to leave so that you can have some time and space to think about what you want.
He's not really taking you seriously.
Oh yes, and insist he goes for an sti check, and make sure he shows you the paperwork. I know he said he was careful but he's a liar and it's not worth risking your health over this. It would also send him a clear message that he should take responsibility and do what's right.
In fact, it would be a good test. Tell him it would put your mind at rest and see what he does. I bet you he doesn't go to the clinic. He won't even do that for you.