Here's a thought that helped me get through those awful times too. His addiction wasn't about me. Meaning..........he wasn't leaving me because I was this horrible girlfriend. He wasn't leaving me because he fell in love with another woman. He really didn't want to leave me LOL.
He stayed gone and treated me the way he did because he was addicted to crack. The drug became his love, his obsession. His behavior had nothing to do with me and for me, that gave me some comfort. I hope it do the same for you honey.