The last time this happened to me (thankfully a while ago), I was the girl in your story. Once my heart had mended some months (years?) later, I had a feeling she (like the guy in your story) had just wanted to string me along, just in case things didn’t work out with her new guy. I had to make the cut. Doesn’t mean I stopped loving her, but I had to move on. A part of me will always love her or at least the memory of what I thought we could have had.
We met up some years later. Ironically, our situations were nearly 180° swapped from how they were when we met the first time (although that also wasn’t the first time we met, but that is a long story). Of course I still had feelings for her, and I believe her feelings for me were genuine as well. But by then I really had moved on and was not going to jeopardize my current relationship, so there was another cut.
I have resisted contacting her again either remotely or when visiting her city. Better I think to just enjoy the memories of a love that just wasn’t meant to be.