Hi Helen
re your post of 18.05 that I have separated out for my comments to be added.
"@Nat1833 its a shared history, the possibility he might cut down, the upheaval for the kids and wider family connections - i just know my MIL will be round crying and trying to get me to reconsider, how it will work out split parenting, finances especially at the moment".
NONE of these factors are and basis, let alone reasons to stay with your alcoholic and your codependent nature also keeps you tied within this. The shared history is another form of sunk costs fallacy (do not get bogged down in your sunk costs) and hope is false here also when it comes to him. How many times have you covered for him and or hoped already that he will stop drinking?. You really do not want to waste any more years here on him hoping for him to have some epiphany that won't happen. His mother is probably glad that he is off her hands; besides which she does not live with him. You do and your life with him, let alone that of your kids, is miserable. He won't likely want to see the kids much post separation and could palm them off on your MIL. They will also interfere with his drinking time.
Your own recovery from his alcoholism will not start until you are separate completely from him.
"Worrying for my husband how he will cope and will he get worse with his drinking, upset for kids etc 😢 plus, its just kind of crept up to be like this."
Again this is your codependency talking; you cannot afford to listen to that voice anymore. Abuse like this too is insidious in its onset and does creep up on people unawares.
"Little things like shouting at me, slamming doors, little digs all over time. Its almost- is it worth leaving over that?
These are not little things either in the context of his alcoholism and yes its absolutely worth leaving him over that.
"Then it gets to now and its built up to my “rock bottom” and i have to do something or live like this for the rest of my days"
Yes, those are the choices. However, you also have a choice re this man and your children do not. I would urge you to not live like this for the rest of your days.
"I will say, i met up with my girlfriends and told them my plans. One of them said dismissively to me, well he drinks no more than X and hes still functioning/working etc. i was a bit annoyed. This level of drinking is not ok"
Ignore the dissenter in your group here who said this. Friends too can be overinvested and or unhelpful. Its of more use to write on here to be honest and to find people like you. You could well do with attending both AL-ANON and CODA meetings; there are ordinary people just like you there.
Your H is still working, well for now anyway, until that wheel falls off which it will do. You really do not want to become his carer either.