Really need advice ASAP.

We have a 2yr old and I'm also 20 weeks pregnant. I don't know what to do anymore I'm so unhappy cos he blows so much of our money towards it. I am very strict and I don't spend a cent unless it's for something for the house or the kids that's needed where as the money he spends there's nothing to show for it at all. 

I've cried and got angry at him so many times and he will tell me it's his last time or that he will quit or slow down and it's making me very unhappy in this relationship. I feel like the money could be spent on things for our kids, our home or even to pay bills. 

Even if I delegate money to him as his personal spending I thought this would help him be more accountable so he can realise what he is wasting but even then once it's gone he will then ask me to transfer money into the bank so he can buy more... I have tried to put my foot down and he will hassle me all day until I give in to him. I am just sick to death of it and don't know what to do. I have accepted that he smokes and we've talked about it and I've said you need to slow down because we can't afford ur habit but he hasn't slowed down at all. 

I restrict myself from any luxuries in life because basically all of our spare money goes to his smoking. It's really unfair and I hate him for it. He has spent thousands on it in the last few months and I've told him this and he continues to want to smoke and give other people out hard earned money and leave us to struggle. 

UPDATE*** 

I don't work at the moment I was very sick this pregnancy and had to leave my job I'm only just feeling 100% now at 20 weeks so I'm at home with our 2 year old. We're also in Australia so weed is literally in a tiny tiny satchel bag for $30... I've told him he needs to slow down and smoke what he can afford to smoke but that hasnt worked either he still expects more money once he's used his spending money.

This is what the problem is. I always seem to give in to him I can't ever stay firm on my NO. 

Basically we combine funds cos it's the only way we can afford to pay all bills and then we pretty much have $200-$300 left over and he pretty much uses it all if it's in the bank and he's aware of it. So I'm not left with anything... I've tried to split what he have left over so we get about $150 each BUT once he's gone over his limit he knows I still have mine and will ask for a loan or something stupid. 

A lot of people he knows smoke and so do their partners. To me I have no problem with him smoking weed it's the money that is affecting us. He is a great dad and what not but this one thing is a major issue and it's the only thing we fight about. I have told him that as a parent I need to put the kids first and our small family and keep that leftover bit of money for back up in case anything happens.. he always thinks nothing will happen and that we will be ok. Every single time he does this it's his " last time". I am over the excuses. I just don't know what else I can do from my point. I don't want to be one of those crazy girlfriends  as he thinks it's me controlling him but like I said it's not about the smoking it's about the money. I can very well live off little to nothing but having a small family is my priority not his smoking habits, this is what I'm trying to get him to understand. He knows all the bills are paid and we have food and everything to last us but if he knows there is money there and he is out of his smoko then he asks for more money.... I don't even want to add up the amount he's spent cos it's just ridiculous. I could have paid my car off or went on a holiday etc. we live week to week be cause he has this habit. I don't go shopping or buy nice things for myself cos just don't have the funds too but he can afford to smoke. There's no compromise and it's killing me right now....