You are needing reassurance that he is not going to end this relationship. You want happily ever after rehab but that isn't always how the story ends.
This is the time that YOU need to focus on YOU. What kind of help did you seek while he was in rehab for 30 days? Are you involved with al-anon, nar-anon, therapy? Have you researched addiction, addict behaviors? Have you learned as much as you can about addiction, relapse, after actions plans? Have you researched codependency, codependent relationships?
I would respect his need for time to work on himself while you work on yourself.