How do you know it's time to end a relationship?

I’m currently pregnant (6 mo.) with twins and have two other children. I quit my job due to pregnancy complications three months ago, so my bf got a job. Typically I am the breadwinner and have worked my as* off since I was 15. He would normally stay home with the kids while I worked. (We have been together for about 10 yrs.)We don’t have the best relationship, but he lives with me and is the father of all of my kids. He’s horrible at managing money and also has a gambling and drinking problem. I had money in two separate accounts to buy things I need and pay bills\for me to fall back on. He drained them both and didn’t even tell me. And all he says is, “the next check will be all yours.” Even after we had a long discussion about saving up for the babies, I’m to the point where I want to sell my house and move away to get away from him. I know with two newborns on the way, I’m going to struggle hard. Not to mention I don’t even know where I would go. I pretty much only have my mom to help out here and there with the kids. (Not often). When I talk to him about it, he says he knows he needs to change, and yet he makes zero effort to. I’ve even mentioned therapy, and he refuses. He drinks at least 5 out of 7 days of the week. Lately, when I tell him how I feel, he tells me it’s my hormones, and I’m overthinking/ overreacting. I’m sure I am more emotional at the moment, but I feel so used and taken advantage of. I’m also not used to being off work for this long and feel like I need to get a job so I can build my savings back up. He doesn’t help me with anything around the house(besides taking the trash out), and it’s really exhausting. I feel so lost/stuck and don’t know what to do anymore. I feel like I’m watering dead flowers here. Does anyone have a similar experience or words of advice?