best friend

At the beginning of this year I was put into a really bad position. My boyfriend basically made me choose my best friend or him. I'm not sure what I was thinking, and why I even chose him. They both mean a lot to me, but my relationship is quite rocky right now. I think I did make one of the stupidest decision of my life. I regret it every single day. I want to be able to talk to her again, but I just don't have the courage or confidence to because I'm sure I hurt her a lot. We were each other's only friend for 6 years. I miss her so much, but I can't get myself to message her. I just want to know how she is doing. I know I will never be able to get our friendship back to where it was, but I really need some encouragement or advice.