Hi and Welcome, I'm sorry for the situation you are in and I know it must be very upsetting. My suggestion is to focus on yourself, your child and your unborn baby. No amount of ultimatums or drives to rehabs are going to change things for your boyfriend. He will need to make the decision to be sober for himself. And, I'm sure that your child is attached to your boyfriend, but keep in mind that he will be a negative role model for the child and that's really important. Do you have any family that you can lean on at this time?
I hope you continue reading and posting. We do understand how hard this is for you.