There are of course legal issues if he gets busted. As long as you are not using, there will not be any drugs getting to the baby. I do hope you know that this is a serious situation if you plan on raising a baby in a drug environment!
As far as addiction for the baby at birth...no....you may need to get him to get tested for any spreadable diseases if he uses a needle....having a dad who uses heroin if he does not quit, would have its consequences in the longer term scope of things