Beautiful, of course he says that, he has no intention of changing, he is trying so many tactics! Sympathy, excusing himself, blaming you (again), medicalising his behaviour, promising things...
He will not get a sleep referral as he won't dare spin his line on that to a health professional, he knows it won't stand up and will give rise to big concern. his alleged sleep problem causes him to sexually assault and rape you and claim he didn't know what he was doing! Hmmmm
Any GP would get big alarm bells immediately!
Counselling (joint) is not a good idea with abusers, as it can become a forum for further kinds of abuse.
a book sometimes rcommended here is Lundy Bancroft "why does he do that?" www.lundybancroft.com/?page_id=142 It argues that abusive men, who may say they are like they are because of their chldhood, bad experiences, or whatever, actually choose and feel entitled to abuse.
Really glad you're now in touch with Womens Aid. Also great that you have your own room.
With respect to staying with your DH for the sake of your boys, how about planning to leave for the boys? You're being mistreated terribly, and have been so miserable at times recently that you've felt suicidal and like you have to leave the boys. Living with a man that does that to a woman is not good for children, even if he treats them impeccably. They could grow up thinking that how he treats you is normal, they may begin to treat you like he does too, or treat a future wife that way. And you would continue to be abused and unhappy, and find it hard to parent them the way you want to.
Maybe for now it could help to disengage from debate with DH to, hopefully, make his day to day behaviour a little easier to cope with and reflect quietly on what you might do next.