8 year relationship over! help!

I've been with my partner for 6 years and his fiancé for the last 2. A few months after our engagement, I found out he was addicted to drugs for at least 2 years. There were many arguements and he finally went to rehab. After 3 months, he relapsed and it started over again. Finally, he went back and completed the program. When he came home, he said he wanted a break to focus on himself. I was shattered! I gave him his break and returned from a vacation a month later. He never contacted me when I was away, and was going to have his mom get me from the airport. I had hope to save us, but when I came home, he stayed at his sisters and told me he cannot live with me anymore and needs to focus on his sobriety. Said he needs to start fresh and not have any reminders. I do not drink or take any drugs. My heart is broken! I feel abandoned.  I stuck by his side and I am in no way a negative influence. On the contrary, I'm very positive, empathetic and would do anything for him ...my whole life is changed and I don't know what to do.