I was the poster child for "I'm going to stay loyal and be the one that can help him." I failed. I was also under the assumption that I could love the addiction out of him; that if I just stayed and helped and was supportive, the drug use would stop. I failed.
I was so sure that I could drag him to detox, allow him to see the light, and everything would fall into place. Again, I failed.
Your boyfriend's intentions may be good BUT you need to do your research on heroin, it's effects, and withdrawal symptoms. Heroin makes the user feel like they physically need the drug, but it's also a mental/emotional thing. Just detoxing (if that's even what he's doing, which it doesn't sound like he is), is not enough to stop a heroin addict. He needs therapy, and a lot of it. My boyfriend initially tried just going to detox, did his 5 days to "get through the withdrawals" and then swore to me he'd come home and things would be okay because he wouldn't be going to through the withdrawals anymore. He relapsed less than a week after detox. Heroin takes hold of the addict's body AND mind.
My boyfriend is doing well, but this is not just because he stopped shooting heroin. He's doing intense therapy as well. The addict needs both components of recovery for it to be at all successful. I mean, if you think about it...you really need to have some serious emotional baggage going on to be sticking a needle in your own arm.
Do your research on the drug so you are informed. The scariest part of my boyfriend's recovery for me at least was how little I knew about what was really going on. I really just knew what he was telling me...Trust and believe, your boyfriend is not telling you everything.
There are many options for him to get help. He can go into a detox facility, a rehab (outpatient or residential), a sober house, etc. If he wants the help, it's definitely out there. NA and AA meetings are great once he's detoxed and gone through withdrawal. Unfortunately, to get off of heroin, usually the addict needs some kind of facility to aid in the detox.
Get yourself educated on this. When I found out about my boyfriend's drug use, I read just about everything I could get my hands on. I read every story that related to mine, every story from addicts themselves about what it's like, what they've gone through, I read success stories, I read horror stories about overdoses, what happens at a detox facility, rehab, NA meetings, etc.
Read/research all about this. It'll be eye opening to you.