Please make plans to leave him, for your own sake and that of your unborn baby.
And also go to Al Anon together support for yourself.
You need a twin track approach as it takes much longer that you think to find somewhere new to stay. You don’t want to be moving house when you are 38 weeks pregnant , especially if you have no family support . So don’t wait to see if whatever he promises to do now actually works.
Do you have friends or colleagues who would rally round and help you for the first few weeks on your own with baby? Even someone coming round after work for a couple of hours who brings some dinner and watches baby while you shower etc can he a huge help.
None of this stops your husband getting his own help to address his issues. And if he gets sober, there’s nothing to stop you reconciling a year or so down the line, if that’s what you want. Either way , he needs help to be a safe and good father for the next 20 years , what ever happens to your marriage.
I know this is tough talk, because you are used to putting him and his needs first. That’s always what happens with addicts, it’s so gradual you don’t even notice until you stop doing it . But you don’t have that option anymore. You will soon have a tiny baby totally depended on you and you won’t have the mental space or physical energy for anything else for a few months . No one warns you but that’s just what happens - it’s all consuming. I guess it’s natures way of making sure that babies survive.
So your husband needs to seek help now. Or continues down to his rock bottom. You leaving might be it . Or it might be baby’s birth. Or even never getting to see baby because he’s not safe. No one knows, not even him.
But threats, promises, begging, pleadings, logic, negotiations etc - they will do sweet FA. You can’t do this for him. You are powerless.
Im so sorry, I wish I could tell you to do X Y and Z and that will fix it. Eg Send him to the GP / get him into rehab etc. But nothing NOTHING will work until HE wants it. Not you.
You need to save you and baby first.