Morning @MrsJaneyLloydFoxe
I lost a partner to alcoholism at 51, I know how horrendous it is. Don't let anyone tell you that this isn't serious, that it's just a blip after 18 months or similar - the sort of relationship to alcohol that your husband has is always serious and always detrimental to those around the drinker. For you to be going through this with young children including a little baby is ghastly. We know the damage experienced by children of alcoholics - it negatively affects their whole life.
Those who have posted before have nailed the key things you need to be thinking about - mainly that you didn't cause this, you can't control it and you can't cure it (the 3 Cs of alcoholism.) Ultimatums don't work, because the person with the alcohol problem has to want to stop for themselves, not because they fear particular consequences. Those afeared consequences can be part of what supports the decision to stop, but they can't be the main incentive. Someone at Al-Anon said to me years ago that you can put someone who genuinely wants to give up drinking in a house full of alcoholics and they'll still stop. It'll be harder, which is why there is the need to remove 'temptation', offer targeted and constant support and so on, but if the person does want to stop they will, regardless of circumstances. Conversely, she said, you can give all the support in the world to the drinker and if they still want to drink, they will find a way. This was definitely the case for my late partner. Those around her did everything possible, in the end we had to detach with love as they say. She died within 8 months, and she wasn't what everyone thinks of as a typical alcoholic, she was a successful professional.
There are some great people on the Alcohol Support threads, partners of alcoholics who have been where you are, adult children of alcoholics, as well as recovered alcoholics who are very wise and honest. I'd head over there for more specific support from those who will know best how to help you. If you don't want to start your own thread yet there's a great thread called something like 'Support for People Affected By Someone's Else's Drinking." That might be a good place to start. I think you'd benefit from some informed advice before you even start to think about how to address this with him, that might stop you getting into a mire, because this stuff is very emotive, especially when you have someone you fundamentally love in front of you, who appears vulnerable, but who has caused you so much worry, sadness and anger.
Look after yourself and your children first and foremost today, and in the days going forward.