I'm so sorry OP, but there isn't anything that will magically make your marriage any better.
It can't improve when there's only 1 person even trying.
Your H is a walking, talking bloody contradiction ffs, and no matter what you do or how you twist yourself into a damn pretzel for him, he'll continue to blame you and his own kids for his self-destructive spiral.
He doesn't agree with vaccines, yet he's happy to use drugs that are mixed with who knows what.
He calls his own kids horrible names, but he doesn't parent them at all.
He blames you for all the decisions HE made to move to the UK, but does bugger all to improve your situation.
He uses the money YOU earn to buy drugs, because apparently UK wages aren't good enough for HIM (but low wages fine for you apparently), which makes his mental health as well as your finances worse.
He destroys your home when he's angry, and doesn't care if that frightens you or your kids and he never even bloody pretends to apologise.
He frequently tells you and his kids that he doesn't want you, or them, he just wants you all to fucking disappear so that he can live alone with a dog ffs!
He doesn't contribute to household chores, cooking, childcare (unless forced) and actively seeks to undermine everything that YOU do.
He says you've turned into a 'Mammy', but he's refused to even try to become a bloody Father!
He wants to be able to do all that, and he's HAPPY to continue to do so, and yet he still expects sex from you???? And complains that you're not up for it????
Who the hell could EVER find THAT attractive?
Who the hell would EVER want to have sex with such a miserable, misogynistic, selfish, nasty, vindictive, aggressive 'man'???
Nobody in their right mind would.
It's time that you stopped putting HIS needs/wants before your childrens and your own needs/wants, because you're actively allowing him to ruin all your lives by accommodating his every bloody desire!
You and your DC deserve so much more than the contempt and selfishness he showers you all with.
Do you really think that your kids will ever be able to get over the truly horrible things he says and does? Will you?
Please, please take the first step by telling your family the whole story. Allow them to care for you and the kids while you get divorced from him and begin anew without him.