First of all, society may not rejoice over single motherhood but it no longer carries the stigma it once did. And you would not be a single mother- you would be a divorced mother and that is wholly different.
Is there no family that could help you get on your feet at all? Either way, he will have to pay child support if you split and with the little you'd be making, you'd qualify for assistance. You might even qualify for assistance in getting that GED.
In the meantime, since he is making no effort to help you reconcile, please read about the 180. Start looking at your options and getting your ducks in a row. Don't give up on trying to better yourself. If you have some employment services places in your area, go in and ask for help. Some places will do placement testing and even help you get back into school. They can also help you look at your job applications to see if there is something in them that makes you undesirable so you can reword or improve it.
You're not worthless. Don't accept less than you deserve. You deserve a husband who is transparent and honest. His continued contact with the affair partner and her family is unacceptable. Remember to eat and drink plenty of water so you stay healthy for your child. Start doing things for yourself.
This is where you will find the tactical primer for newbies who don't know what to do when they first get here:
This is where you will find information on understanding how to do the 180 with an unremorseful spouse:
And this is a selection of great posts for newbies:
Keep posting here. That's the first big step toward this mess improving for you.