My Husband lied to me for MONTHS.

I'm 27 weeks pregnant. 2 weeks before I found out I was expecting I had quit smoking anyway. AS soon as I told MY (now) husband he promised and swore on our unborn child he'd be right there with me. So we planned a wedding and it was beautiful but at the reception I stepped out and caught him puffing on a fag with all our friends and family. I'd be going round telling everyone how proud I was he'd quit and how much it had helped me be strong too and unbeknown to me he'd never actually quit he'd just hidden it from me. Que a MASSIVE row on our wedding night, I explained its a deal breaker for me I explained I didn't want to go through with the pregnancy if we weren't both ready for it. I am only 24 and I've lost all my grandparents and step grandparents to smoking related illnesses. My aunt is a smoker and has just been diagnosed with cancer and he has lost his grandad to lung cancer also. It's not a big deal to some but I have anxiety and it's just a big worry in my life. Again he says he's sorry and again swears on our child's life and our relationship he will quit. I say if you struggle let me know we can go to the doctor or get you a vape try hypnotherapy etc... I just want to support you and even just cutting down will be better than nothing. Preparing for a baby is hard and yes quitting now will be extremely difficult but just try. The wedding was at 14 weeks fast forward to now I found a pouch of tobacco in his work stuff--I was sorting his trousers for the wash and checking there was nothing in the pockets. Turns out yet again he never actually quit he's been hiding it from me this whole time. Again. (I know, more fool me). I've had addictions in my life, I fully understand I cannot force him to quit. If he's not in a time in his life that he feels able to do that I can't make him. However he does know this is a deal breaker for me. I don't want to raise child with a man who prioritises his needs over the child. Money is extremely tight for us and tobaccos is £20 roughly a week for the amount my husband smokes. That's fuel for his work commute. We have a joint account he's been lying about spending our money. He's made all our friends help cover up his lie. I feel like a terrible wife I I leave him, but I feel like I'm letting myself and my child down if I stay. If he has lied this long about this what else has he deceived me about? If he can't come to me for support to help him and least cut down or switch to a vape maybe our relationship was too flawed to even begin with? What do I do? Stay and compromise my morals, or leave and break up a family that's barely begun?