My advice is.. and its your life so do what you feel is best for you, so dont be saying.. im not taking any advice off him lol
So you could either.. if you still want to be with him, move him back in on the condition he cleans his act up, stays away from bad people and help you and the baby. Your going to need rest when the baby is born and help with night feeds and so on. It really is draining.
He cant go awol and have his phone off. And he gets help for the coke.
Im only saying this because if you want to be with him and not living together, it will be a lot harder for you and he will just be on that stuff most of the time.
Or just go it alone, if hes not prepared to get his act together. Which will be hard for you. But it will just make you ill. Most women on here will tell you get out now while you can who have partners on coke. And they are right. But time is a great healer.
But i hope you sort it what ever happens.