4 years and now living apart

so my partner and I have mostly lived together for our 4 years relationship. Recently I have had to move for career development ect. I was under the impression he would move down quickly. Now he doesn't know when he will be coming here. granted, he's staying there for university which is fine. We weren't talking as much as I'd have liked and THEN he phones me crying because he's got addicted to cocaine. I've only been gone 2 months. He's says now he's going to change but he's done this before. He's 28 years old and I've constantly supported him and encouraged him to reach his potential. We are doing this to better our lives but I just feel like this will be another failed attempt for him. Do I wait and see again? btw he has previously started jobs, apprenticeships ect and not committed or finished and we always suffer financially coz he doesn't match my work ethics.