Sorry for the pain that you are feeling. I too am going through a recent loss of a relationship with an addict. Try not to beat yourself up thinking that you are the cause of his relapse. Relapse is not a single event of the actual moment he hung out wit his old buddies and used. Relapse is a series of problems or a process that happens before he actually used. During a relapse someone can start having emotional difficulty and start thinking and behaving in old ways and decide to use. Sometimes even after sustained recovery when life gets stressful going back to the old life can seem easier than trying anymore. Such as... him pushing you away and deciding to contact people that he had full knowledge would lead him to getting high. Also, you cannot be comfortable in a relationship where you have to walk on eggshells that expressing your feelings or getting into any disagreement/argument is going to cause him to push you away, break up with you, and go make poor choices. No doubt because of his past he would have fear of abandonment and trust issues and this is just my opinion but sounds like this is his way of coping by pushing you away and like you said, hurting himself before you or anyone else can.