To stay or to go

My boyfriend is 20 years older than me. I'm 21 he's 41. In a little over a month we will celebrate our 4th anniversary. After our second, I left for two months. I'm a recovering addict and I left because I knew I was about to fall off the wagon (also I wasn't sure he was the one for me for many reasons) After two months, looking around at rock bottom I was about to kill myself (made videos saying goodbye to my friends I just couldn't take it anymore) got really drunk and passed out. I woke up the next day and messaged him. When I saw him again for the first time, it was like everything screaming in my head went silent. Now we've been living together since then, a year and a half... And he's not answering my questions. He always gives me big promises about how we're gonna get married and have kids and none of it is happening. Right now, he won't even talk about it. He's using his recent surgery as an excuse, but I don't consider that a viable excuse because he wouldn't talk about it before the surgery. He just says he's "not talking about it right now" or that it's "not the right time" to move or to even talk about getting married. I sacrificed everything and took some huge risks moving down here with him (left my job without another, my dad threatened to dissown me, we'd only been back together for about a week) things were GREAT. Now that I'm asking questions I'm starting to see our relationship in a different way. He somehow convinced me to give up on the idea of getting married and I'm realizing that I don't know if I'm okay with that. And he's not getting any younger honestly and has some health issues so my concern is that if we're ready to settle down, when IS a good time to start talking about kids. I told him I'm not going to keep asking this forever and... Honestly, in my head the thoughts of leaving are coming so often I'm just so terrified of being alone, finding my own place, not having someone to talk to. I've been saying for 4 years that he's the reason I got and stayed sober and I realized yesterday that he's not. I am. I wouldn't have done it if I didn't want to, but I just have been using him as my reason. What do you ladies think? Stay? Go? What would YOU do? (Sorry I wrote a novel I tried to shorten it as much as possible)