Stuck...Dont know what to do...*long*

I will try not to make this terribly long... Background: I am 26. I had never had any stability in my life. Shuffled from foster placement to placement until I left school and the system at 16 and ran away. I never finished school and have yet to get my GED. I met my BF a few years ago and moved across country to be with him. So, I have no one but him and his mother who has been like a mom to me. Now: I have not had much job experience. My longest job was just under a year that I had to leave because his work schedule got in the way and I started to accrue disciplinary points. Anyway, I really feel like he and I are not working. I have tried everything I can think of to help him and us. He does not discipline his daughter or our son. I do. His daughter refuses to listen to me which is fine cause I give up. He also refuses to pay bills on time. He will leave mail in a pile and not open anything other than cabelas flyers, until he gets past due or final notices. For instance, the power bill is $270. Was due last month, He says "they can not turn us off until April 1st"....annnd that makes it ok to not pay it? Then he wonders why things are so expensive. Anyway, this is how he is with everything. He never picks up his stuff and I have resolved to not picking up his things anymore... My biggest problem is...how do I leave? I have nothing...I am studying for my GED and plan to do that and get my drivers permit with my taxes from my job last year. I have been applying to places but I think a lot more employers are not hiring people unless they can prove they have a GED? IDK. I just want out. He is so immature and I can not see myself spending the rest of my life with him... Do I stay until I get a job? I would need at least 1 full time job or 3 part time jobs to MAYBE be able to afford a studio here...I feel like I seriously fucked up not just my life but brought my son into the world in this situation... How do I even afford being a single mom when the cheapest studio around Milwaukee is $600? 😥 I feel so overwhelmed...