Please help😭

I have been with this guy for two years, he has a daughter and we have a home. We are currently trying for a child.... Everything is mostly happy go lucky until he pops a xanex or two or does it the whole week... I can't handle it. I grew up with family who does these things and I am a recovery alcholic. I just can't handle him when he is like this. I have depression and anxiety really bad and it seems like every time he does this My depression and anxiety goes up. I can never get through to him. I have tried everything!! He is now telling me to leave him if I can't accept this😭... How is that so easy for you to up and say that? I just don't know what to do anymore. I am so hurt by him. Just last night he told me he was going to make me the happiest women on earth.. I am very sick right now and he was taking care of me and everything. Now he is high and just so mean to me. I didn't sign up to go through something like this. I love him so much but what should I do? I feel like he really don't care if I leave. Like it wouldn't bother him. He said it would be my fault if I left... HOW?! I am so tired of being hurt and feeling like I am not good enough. He is the most important thing that has happened to me. He use to be a heroin addict before I met him and I am so scared that he is going to go back. He doesn't care about how bad he hurts me either. I have been there since day one and helped him in so many ways for him to just treat me like shit?? What should I do?

He's been to rehab for Heroin and while doing so he was still using xanex.. He doesn't see the problem. I tried helping him in multiple different ways. So please don't assume that I never did. That's why I am writing on here because I am at a loss