It's so hard to accept this happened to me

Once upon a time, she loved me deeply. We were in a 5-year relationship. She cared for me, and we used to talk almost all the time. She couldn’t imagine living without me, and I felt the same way about her. But then she met someone new and left me. She dated him for just one month, but I don’t know why they broke up.

When I spoke to her afterward, she told me she had loved him so much that she forgot how much she once loved me. She even said that the pain of losing him was greater than the pain of our breakup.

I asked her if she loved him more in one month than she loved me during our 5 years together. Her answer was, “I don’t really know.”

Now, these thoughts keep haunting me. I can’t stop wondering what I didn’t do in those 5 years that he managed to do in just one month to make her love him so much more. She’s in depression over losing him, and I’m left questioning everything. I am feeling so stupid and hopeless that I wasted my love, my time, my energy for 5 years just to get this in last. I am so depressed and there's not a single minute my brain isn't going through any negative thoughts or overthinking. When she'll be over that guy..will she ever truly realize what she has lost? Will she ever come back?