Please help

I just need some encouragement. My fiancé has been using heroin again and I need to find the strength to leave. I'm 5 days overdue and so afraid of doing this on my own, but I know he isn't willing to get better. I cant even get him to be honest with me about it. If he would, then I'd probably stay because at least there'd be some hope that he'd would take steps towards recovery. I've tried so many times to get him to talk to me about it but he just lashes out at me, tries to make me feel like I'm crazy for thinking hes using. I never ever imagined that I would be a single mom, in fact I never really wanted kids until I met this man. So the idea of raising our little one without him is extremely daunting. I know this is what's best for my baby, it's just so hard to walk away from someone you love, especially when you know theyre sick and you can't help them. If anyone else has been through something similar I could really use some words of encouragement.