Codependency + drug addiction + depression = SUICIDE?

OK – I know i’ve asked questions similar to what I am asking, but I have been researching codependent behavior/tendencies & I feel like this might have played a HUGE part in my boyfriend committing suicide or why I was even dating someone who was battling & also engaging in full-blown opiate addiciton. I became an enabable & codependent to this person. He was going through recovery & said he felt like he was becoming addicted to me instead. I tried & believed I could show him a “normal” life without drugs. He was always open to doing whatever I suggested – minus certain music & movies. Anyway, that made me feel good, like I was finally being loved (yes, I must have issues?) He got back into drugs & blamed us fighting for his relapse. I worried about him constantly & became very distrustful & most likely bitchy. I felt like I always had to be responsible & act like the caretaker & this in return, made me resentful & bitter towards him. BTW – he had been struggling w/depression & drug addiction for about 10 years. We were together for 2 1/2, but long-distance, so I only saw him once every month. He also had a lot of anger towards his parents. It was recently stated that maybe he was with me because I reminded him of mother. From what I’ve read, the combo of addiction & codependency never ends well. I am struggling with tons of guilt & feeling like I was with him because maybe I loved the “idea” of this person, but not the person. It makes me sick that I could be like that. We never were together enough to talk about our problems, or actually, they just all seemed to be overlooked somehow & many times he said he never wanted a girlfriend, but that I just wouldn’t leave him alone. I never knew what state of mind he was in, so I would almost beg him to not break up, it was cyclical. Why didn’t I just listen to him & leave it alone. Neither of us were happy. He commited suicide in Feb. He had relapsed in Dec. again into IV drug use – heroin & meth.