Partner smoking

I know it seems silly. It isnt weed or drugs but when we met he never smoked. He did not tell me he did previously when we got together. It noe takes over his life and it has changed him. He sneaks about to do it when im around. His mum enables him and actively encourages it. We have 2 children 4 and 10 and I am just so unhappy. He is so aggressive without it but wont try to get help. Say he wants to give up. He swears at me, calls me all names and twlls me to f off and then acts like nothing has happened. I am now at a point I struggle to be around him.

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