Sap1191

Hey guys new here....
I need advice because I feel like I keep going back and forth and I just dont know what the best option is for me here...
my boyfriend (who I knew had a substance abuse problem in the past) was clean and sober when I met him and always had reassurred me that it was all in the past ... so we have been together for about a year now and he started to act out of character .... I knew he was using again but he wouldnt admit it so I broke up with him, told his family everything that I did suspect... however I didnt have proof except just his irradic behavior and secrets and I told him that when he wants to tell me the truth and get the help he needs to let me know ..... about a month went by and i was getting upset, nervous and anxious and so worried about him. He still wouldnt admit anything and his family decided to have an intervention. The night before the intervention I met up with him to discusss our relationship and was hoping thet he would finally come clean however he just continued to deny deny.... just made me feel like I was going crazy but i knew in my gut something was very wrong....I guess i was almost hoping that maybe I was crazy I didnt want to be right. I wanted to believe him .... but then I found out by snooping that he was using heroin.... i was so absolutely devastated inside I just wanted to help him and was absolutely petrified of him losing his life..... He didnt know that I found his stash and I somehow held my composure in order to just get him to the intervention and then we all told him that we knew and that he couldnt lie anymore... he basically lied up until the intervention and even in the begining was still denying.... he finally admitted to using and we ended up sending him to detox and a rehab on the other side of the country.
I thought i would just send him away and then be done with him knowing that I did all I can do and now the rest is up to him.
My logical brain wants to just let it all go and know in my heart that he has a lot of demons that he has to work on.
My problem now is that since hes been gone only a few weeks im even more worried. Im worried he just went to appease us all. Im worried that he will use again when he gets back. Im worried that he doesnt know the severity of this disease. He says he loves me and wants a future with me but how could we ever have a future now knowing that a any moment he can relaspe? I dont even know where his head is at we havent had much contact since he has been gone. Its just so sad because our whole relationship is broken. Everything is a mess. Everything that I thought my life would be is just a confusing mess right now. Im angry, depressed, sad and ashamed myself. Everyone told me to not to get involved with someone who used but i honestly believed that it was part of his past....
so now im here all alone broken and picking up the pieces he left behind.
On the conversations we have had he says he wants to prove to me that he can do it. That he can be sober and be a better man for me. However how could I ever believe him?
how could I ever forgive what he put me through that month I was petrifed everyday that he was going to die all alone in his apartment. I was happy that i stepped in and got him to go but now im unsure it I stay. I am so confused on if I shoule stay or go? Help him through his recovery or just cut off ties and run away for good. All my friends say that I dont have kids with him and im not married so they said run far away. I wish i could. I mean i guess i could but its just that i love him and care and worry so much that something will happen to him. I also miss our relatioonship and wonder if he does stay sober that we can rebuild and trust again. Idk it it sounds niave and stupid. Idk what to do. Anybody got any advice? Im just so lost and confused.