Should I Stay or Should I Go?

Thank you to anyone who is willing to take the time to read this and help me out. I’m a 24 year old guy, who is naturally beyond stupid when it comes to the dating/relationship thing. I made the mistake/good fortune of dating my best friend. It is both our first relationship. We met in college and we were really close for about 9 months before we started dating. I guess the reason we started dating was because we were in a relationship without any of the “benefits”. I still really love her but I am finding out that I am not in love with her. I was never really attracted to her in the first place, but I loved her for who she is, and was willing to give it a shot. Anyway, we have our differences and I think the only reason that we are still together is because we were so close before and we still have a great deal of respect for one another.
I have another friend who I find myself coming closer to every day. I dont want to say that if we were to break up that I would date her right away (also because she has relationship issues) but I am intrigued. However, I know that I still do love my girlfriend for who she is, and it is really beating me up inside. All I can say to describe her is that she is truly an amazing person, who is thoughtful, who really cares about me like no one else has, she has a great heart and I can trust her 100%
My gf and I argue a lot and I think it has taken its toll on me. I said I dont think I am in love with her, but I do love her. Part of me feels like its time to end it because I dont think things can ever get back to being the way they were and the longer we are together, the harder it gets for both of us and the more I think we hurt each other in the process. On the other hand, I just listed all these great qualities she has and I dont want to just throw that away. In an ideal world, I just want things to go back to the way they were when she was my best friend and emotions arent involved and we are less invested in one another. But no way she goes for anything like that. I feel like we always say that we are going to give this another shot but nothing ever changes, and we end up at rock bottom. Can I really make things better or am I blind? I’m also a softy, so, when se cries, it absolutely breaks my heart. I cant stand to see her cry and thats part of the reason we have this cycle of break up, get back together. When we go through that cycle though, nothing ever changes. Nothing is done differently by either of us. I guess what I need help with, is, knowing whether it can be fixed? Something I should try? Or, do I just realize that things cant get back to the way they once were and that we both need to move on?
Any advice would greatly help.
Thank you very much