Not clear if he's the bio dad of your son, or not. Regardless, addicts and those in early recovery make lousy parents/role models. We codependents tend to make lousy decisions when we are lonely.
It's very common for people addicted to substance to talk about how they are going to get and stay sober while they are high. It's just talk.
He's going to continue to hurt you as long as you allow him to do so. It's boundary time. You and your child's emotional well being depend on it.