How do I get it back, I ruined everything?

In the summertime I had this thing with a guy. He was the one, I honestly have never met anyone so perfect for me. &not only did I have a thing with this guy he was my best friend, we clicked so well, we could talk to easily, I told him everything and he told me everything our personalitys clicked so well. But I ruined it when I met his best friend, who was really cute I began to kinda like him his name was matt and he knew about me and jamie. We were all good friends we all hung out all the time. Id be with jamie everyday from 11 in the morning to 9 at night hanging out with all our other friends tyler, matt, jacob, nicki, hannah, savanna, zoe, jorden, cam and others. We were all so close. I liked them both jamie and matt, I did like jamie more though. One night me and jamie had a very special night and kissed. Next day again. He was planning on asking me out. I was so happy I couldn’t even exlain, most I’ve ever liked someone and I’ve liked a lot of people. All feelings for matt were lost. Untill that day me and matt were down at the dock talking, that night he asked me to slee over. As much as I knew it was a bad idea, I accepted. That night me and and him stayed up way light into the night looking out at the stars, everything was great we kissed and what not. I knew right then, everything was over. On my way home the next morning, I felt nothing but regret. I knew I ruined what I had with jamie. I had no idea that it would have possibly gone as far as it has anymore. I lost my best friend jamie from this. Its been almost 4 months from what has happend, and he still hates me. He wont talk to me, he hardly looks at me. We still hang out with the same croud every now and then and its just so weird. He hardly acknowledges me. It really hurts. No matter what I dont think my feelings for him will ever go away completly, and I dont think things will ever be the same. We’ve tried taking about it so many times, trying to fix it, and it always seems like hes up for it, but its just never works out. I just really want to fix this, so much, more than anything, I’ve tried so much, what would be the best way to fix this? I want my best friend back.