To leave if DH won’t get help

No one else knows the extent really

I suspect that they do. Your children will know.

SIL's late husband was an alcoholic. She buried her head in the sand and was in denial for years. She thought we didn't know, but we did.

His drinking escalated and she stayed with him. We watched him drag her down with him. He had seizures, developed cirrhosis of the liver, developed alcoholic encephalopathy and behaved so erratically that he was eventually put into residential care where he lived for several years until he died. His death certificate says that he died fom alcoholism.

You didn't cause his alcoholism, you can't control it and you can't cure it.
If you stay nothing will change.

Unfortunately it's a vicious cycle and no doubt the drinking is making his mental health issues worse.
The problem is, as an addict he will prioritise his need for a drink over you, your mental health, your relationship and even your kids every time.

@MissisK

I know it’s an illness and I’m trying to be sympathetic but it’s affecting my mental health

The fact that it’s an illness doesn’t mean you and your children have to commit to having your lives dragged under by it.

Ultimately you have to put yourself and your children first. You don’t owe him martyrdom.

It's time to go OP. You and your kids shouldn't have to live your lives walking on eggshells and watching your every move around him. It will also teach them some bad habits about relationships.
If you leave, the best case scenario is that it spurs your husband on to get help when there's no facade that all is well anymore. I warn you this is very unlikely.
Al-anon may be a good place to find some support. I understand your husband is ill, but he is an addict and love and support from you alone won't be able to fix him

The thing with alcoholics is that you can’t really influence them. You can reason, plead, cajole, nag and issue ultimatums but ultimately alcohol will always be more important.

I was married to a just about functional alcoholic for 12 years and spent most of those years bargaining with him in various ways to cut down, to stop etc.

Its actually really freeing to accept that you can’t control it but nor do you have to live with it.

The brutal truth is most alcoholics don’t stop. Those that do manage to do so because they have had a huge epiphany, reached some sort of bottom and decided the choice is life or alcohol. Your partner clearly is nowhere near that point and won’t get there because you are asking him to. It doesn’t work like that.

You need to accept that you can’t control it and then ask yourself if you are prepared to accept it. If the answer is no you have to leave . That may or may not trigger him to reassess his life. But you can’t count on this. Do it for yourself. Your life will improve without the weight of having to constantly worry about it. Whether he chooses to sort himself out or not is down to him.

I didn’t have kids with him but we were married.

I left when it became clear over a number of years that even if he told me he’d stopped, and did seem to stop, even for a long while, I would NEVER be able to fully trust that he wouldn’t drink again. No matter how long it was or how much he promised, he’d always be one drink away from the gutter.

He died of alcoholism aged 39.

Well obviously he knows he's an alcoholic.

I think it's important that your teen children know exactly the score. You don't want them to think this is normal drinking do you.

I think your dh should talk to them and be completely honest about his alcoholism, for their sake.

As for staying with him - is his drinking impacting on his work, sex, health, your social lives?
What does he want to happen if he gets alcoholic related dementia?

He has to decide himself to get better.
Don't tell him you're going just leave and if he gets better you can take it from there. If you stay this is your life. Are your friends and family aware?