We tend to think of the world in black and white. For example, thinking that we only have two options in a situation. But the world we really live in full of color...and there are almost always many more than two options.
From your letter, here's what I know about your boyfriend: He's a binge drinker and an alcoholic. He's in trouble with the law. He's unemployed and living off your income. He's going to jail, rather than pay the fine. He's a drug user. He doesn't want to stop drinking.
Yet you love him and want him to raise your child. The heart wants what the heart wants...but a lot of the time, the heart needs to take a backseat and let the brain run the show.
You're working two jobs. That may not be enough to support you and your alcoholic boyfriend, but surely it's enough to support you? I mean, you're making it and think how much money you'll save not buying alcohol and pot and with one less mouth to feed.
You know, the reality is: This has absolutely nothing to do with your boyfriend. This is all about you, what kind of life you want for yourself, what you're willing to settle for in a relationship and why you're attracted to bad relationships.
You may not even drink, but you've got a problem with alcohol and it's making your life unmanageable. Try this: Get on the internet and look for an Al-Anon meeting in your area. Al-Anon is a support group for the family and friends of alcoholics. Make a commitment (to yourself) to go to six meetings. Some people say 6 different meetings, but I think it takes a few meetings just to get a feel for how it works. And just listen. You won't be asked to speak--but you can if you want to. You'll find the people are warm, supportive and they don't judge. They are going through the same things you are. When you get the courage to speak about your own situation, (and I believe that you will find that courage), you'll find that sharing brings a real sense of relief. And you'll find that your "secrets", the things you can't share with your parents or your friends, look a lot less scary once they see the light of day.
I really hope you find what you're looking for here. Both you and your baby deserve a good life, and raising a child is hard work. Raising a child and supporting an alcoholic may be too much for you. Eventually, most of us here have found that alcoholism is too much for us and we all needed help to deal with it, and to heal from it. Best wishes for you....