Mistake of staying friends

Me and my girlfriend broke up about a month ago. It was because I couldn't change and I understand that some will say that you will need to find someone who will love you for you without changes. However, she was right. I did need to change some of my habits and lifestyle. But I didn't think it would lead to her losing her love for me and breaking up. In all honesty, I was trying my best to change and there was definetely some progress, but I guess it wasn't good enough.

After the breakup we stayed as friends which was a huge mistake. One day, I called her and noticed she was ill. I asked about it and she told me she went out clubbing with her friends. Immediately I got suspicious and asked whether she slept with someone and she said yes. The fact that she was able to move on from a 3 year relationship within 3 weeks just broke me. Not only that, she also said that she doesn't love me anymore and that I should move on. I decided to break it off completely and go no contact.

I still love her and from time to time have dreams of us being back together which is pathetic of me considering how fast she moved on. Should I move on? Is there a chance of getting back?