Friends. Betrayal. Hope? mostly a vent.?

Alright. This is about the second time i have been thinking about doing this. Here is my problem. I had a friend that asked me to talk to this girl for him. So i did without any questions to why. At the time me and this friend were cool. But while i was talking to this such said girl, i developed something of a crush on her. Long story short, i went behind his back and went out with her. Oh did i mention that i we were both going out with someone else while this was happening? So BOTH of us broke up with the other person and got together. My friend as you would be able to guess doesn't like what i have done and disapproves of the whole relationship. Which is completely understandable. I feel like i broke probably one of the only person i trust. Feel like a d-bag. But that isn't the worse part. My friend and I got together earlier last week. I told him i felt bad about the whole thing and i wanted to make everything straight. Where it was suppose to be. Him and her together. (Oh i forgot to mention this. My current Girlfriend ,which is the girl he wanted to date, really did like my friend. I was just the one she talked to first so she went out with me. So while we are dating, she STILL likes my friend and texts' him all the time. I asked her about it and she said she would never hurt me. But she did to her boyfriend before so that we can get together. Interesting no?) So me and my friend talked. And at the end of the discussion we thought it would be best if i broke up with her. So that she could be happy with him and me and him will have our old friendship back. (Me and the girl have been fighting ever since we went out. KARMA) But when i tried to break it off it hurt. Like a stab in my side to even think of doing it. And she said it felt the same to her. She said that she chose me and that is who she wants. So to make another story short.. we are still together.. and now my friend is in a even worse mood then he was in. He officially hates me. How can i fix this? Is there anything for me to do? Or am i just a Grade A D-Bag. I feel so bad for this whole thing. Kinda want to start over. This was mostly for a vent. Don't feel the need to respond.