You may not be beating on a dead horse -- yet.
While it isn't for us to question your boyfriend's apparent love for you, what we can ask though is whether he will be a worthy father to your baby. Babies really change everything. If a woman thinks she can take anything a man can dish out, that isn't necessarily the same thing when it becomes a question of how this man will be as a father.
If he can't kick the drug habit, he won't be sober enough to help you out. Even if you're the silent, suffering type, don't allow this to happen to your kids. Imagine being unable to stand because of some labor pains and he's top stoned to help you. That effectively puts you and your baby in danger.
If he really loved you, he'll do everything in his power to turn his life around. If he can't show the maturity that is required of a father, it may not be a good idea to have him around.
On the other hand, a child does need his/her father. While it may be a while for him to kick the habit, if he at least starts showing that he can go to rehab and find a job, no matter what it is, then maybe he can be a worthy father.
Love him, yes but love your baby more. It's not just your ability to suffer and bear being him that's the question here. You have to think about you and your baby because that baby cannot defend itself and fight for what is right. You have to do that even if it means teaching the father how to be one. Fatherhood is not a matter of shooting sperm in someone's vaginal canal. It's mixing formula, cleaning the butt that's coated with gooey poop, replacing the soiled diaper, getting a job that will pay for school stuff, ladidah, ladidah. You know the drill.
Take care and God bless you.
Erick