Ruth -
Yes, it is possible he won't do it again. But it has to be HIS decision and something he wants for himself. I am a recovering crack addict and after being clean for a while, I relapsed. THAT was when I decided I never wanted to go back there.
One word of advice....it's not YOUR responsibility to "make sure he goes to meetings". He has to want to go to them for himself, or they will not help him. Meetings don't cure an addict. They only help the addict deal with life and not use. If he truly wants to not use again, he will do the "work" to ensure he doesn't use again (and it IS work - you have to learn other ways to cope with life). But if he goes to a meeting just because you want him to, he will end up resenting you and will get nothing out of it.
Keep posting here, and read other posts. The wonderful people here can help you to learn what is supporting & loving, and what is enabling.
Hugs and prayers!
Amy