HMC
Welcome to SR.......I'm so glad you found us but I'm so sorry for the reasons that bring you here.
Your screen name says a lot......how many chances do you want to give him? Just as your boyfriend will only stop when/if he is ready, you will stay until you just can't deal with it anymore. When the pain of staying with him becomes greater than the thought of leaving him.....that's how many chances you will give him.
Most addicts won't stop until they begin losing......like losing the people they love. My son had to lose everything.....all of his possessions, his entire family, his job. He was homeless and couch surfing before he decided that enough was enough and he decided he needed treatment (for the fourth time). And I don't know if all of that is enough to keep him sober.
I hope that you'll stick around and learn about addiction and about yourself. As the child of addicted parents, you may find support in the Adult Children of Alcoholics/Addicts Forum too. Many of us visit and "hang out" in more than one of the forums on SR.
gentle hugs