My xh was a heavy drinker, 'beer boy' apparently. Good job, functional, just very sociable, charming etc. I can tell you right now having a baby does not change anything with an alcoholic and it is so damaging for the children. I thought he would change, he promised me the world. But the problem is with an alcoholic (and alcoholics all vary in the amount/type of drink/ frequency - what is persistent is the behaviour and reasons for drinking) is that when they promise you the world, they are lying. Not to be horrid, but it is all part of their illness and alcohol is number one priority. It might be disguised by 'but I was stressed, needed to unwind, seeing my friends, need freedom...' but basically that pint of beer is number 1. Over and above you and over and above your baby.
When I was pregnant, I would get phone calls from his friends telling me he was paralytic and on his way home, he would leave them, get on a tube, change direction and head for a party - somewhere. I drove around the streets looking and worrying because I didn't know what had happened to him. Once the baby arrived, I got angrier with his behaviour and the arguments got worse. I brought up young children on my own, because I could not rely on him to be home or sober. He could be on the phone, promises galore (on his way home, make dinner together, read to the children) and still disappear into a drinking establishment within a minute of hanging up. He could be literally 3 minutes from home at that point.
He was highly functional, one type of drink, only after work, not every day. If pushed could go for months without it. My children were used to hearing arguments from newborn, as my way of dealing with it initially was so fight him and confront his (awful) behaviour. I then realised that didn't work, so internalised all my feelings and tried to manipulate him. All that happened was - he didn't change. Actually, he did. He got a diagnosis of depression, and that just escalated his drinking and entitlement of space. He would let me know if I confronted him, he would kill himself and told me how. He has all the treatment money could buy, and never admitted his drinking problem, so nothing changed. Other than his new diagnosis meant he now did absolutely nothing with the children, has a lie in every day, and gave himself lots of treats. On top of the drinking.
Either way, it took a breakdown (me) and lots of therapy to realised that I would probably end up dead from stress if I stayed with him. I put down boundaries for the first time in my life, he broke them and he left. The children never once cried or asked where he was, he had been so absent in their lives. Living in that environment, his behaviour and the arguments has definitely damaged them. Even though I tried to shield them. But they are getting better every month. We (the children and I) are happy. We had not a bean when we left, he had debt (lots of debt) from drinking and credit card bills. I am now working, and a single mother, and happier than I have ever been. When it comes to living with a charming man like that, it takes every small bit of your soul and destroys it. There is no room in a relationship like this for two people. My advise to myself a few years ago, run run run like the wind and get out of that relationship, beg borrow and steal money for therapy, and realise that at the stage you a pregnant with your first child is the EASIEST time to leave and rebuild your life. It gets harder after that. He won't change. Not for you and not for your children.