JWM30's activites

I read this story a few months ago and I forgot the name of it. The premise was that this girl had undergone multiple reincarnation in which she retains her memories from each, and in each reincarnation she is the girlfriend of the hero but because of some circumstance the hero ends up leaving her in each lifetime and she dies alone. In the current reincarnation of her, she decides to actually do something and it is later revealed that she is the key to defeating the demon lord once and for all since the demon lord is actually the hero from her first life and he went mad when she died. Please tell me if you know the name to this story as I REALLY enjoyed it :D