I'm newly married, with one kid and another on the way.. I think I may need to leave my husband as his once a week drunkenness bothers me.

I just have a feeling that he's with me for fear of being alone and moving on. He's said to me time and time again, if we split he would be dead and it would be the end of him as he would be crushed and destroyed.
A part of me wounder about the guilt as he would probably spiral.
He only lives to make himself happy, does not address any issues and oh we haven’t been intimate since very early June.
I'm just afraid of what will become and what he would do to me to get joint of my kids.

Here's the history (from a previous post of mine):

I'm 32, he's 30. We met 5 years ago and had our share of up's and down's, plenty. After our son was born we started to have difficulties communicating, so many explosive fights had happened around then. To the point of me asking him to move out. He has a huge temper, and a horrible way of seeing things outside of his own beliefs.

During our time apart he moved in with his father for about a year. He drank and drank and drank to the point of obliteration. He would go out to clubs and drink and take klonopin to boot. Within the time he moved out, I'd say about 3 months, he had a DWI with property damage. He continued to drink his life away. Very emotionally immature and unstable he was at the time, I still would let him over at least 3 times a week to see our child.

When he'd come by, he'd just curse at me, give me mean faces and tell me how i was garbage and wished i would just die. Still I let him visit our child. Eventually he met someone who and moved out of his dad and into a new place, and then allowed her to move in two weeks after meeting. I would say that lasted about a month before they started calling the cops on each other.

I decide in order to keep sanity and the health of my child as a priority, to let him take my son with his mother out during "visits" I just could handle him say horrible things in front of my son.

Fast forward to summer of last year when I guess they were not on and off, he started drinking 24 hours a day. He would drink during work hours at home alone and just black out. He said he didn’t like being alone. He did a stint in a one week rehab at the advice of his employer who wanted to fire him for his alcoholism. So he did that but continued to drink and take pills. He got to the point where he would get drunk and decide to come to my house and kick my door to get in. Cops were called and he was brought to psych at a hospital via ambulance. that went on for months. He started leaving me threatening messages and calling me a dirty ***** a *****, garbage, and all other types of explicit words. He blamed me making him leave for all of his problems and drinking.

I guess you would say earlier in the year he decided to get himself straightened out after I cut off all contact and said he wouldn’t be allowed to see my son. He’d call me crying saying how he's change and doesn’t drink and he made all kinds of promises. So after some time we decided to try to make it work, with the agreement that he didn’t drink. Not long after he came home from a night shift wasted. And it's been every two weeks since in moved back in April. Don't get me wrong, he loves his son. And we're now 2 months pregnant. And the arguing every day has returned. His mother is involved in everything, and I believe making things worse, as he only tells his version of everything. He’s the most manipulative immature man, yet not a terrible person, I’ve ever met. Everything is always my fault and he's perfect, and he "only drinks once a week" even though I said I bothers me.
He even got drunk in front of my son a few weeks ago. He comes home from work and only speaks about himself and pretends to be a loving dad to our son by buying him gifts of playing with toys, never teaching him anything about life or reading books/learning.