I tried searching for this manga yesterday thinking that I save it but didnt. Its about the female lead being reincarnated I believe 7 times and each time she is her lover turns out to be the hero in each of those timelines. The male lead is also reincarnated all those times with the female lead. Each time the female leads dies because she was involved with the hero so where the manga takes place when her lover is announced hero she leaves everything behind and starts fresh. However, the hero comes finds her. Turns out the first male lead timeline the hero turns to the demon king after his lover is killed and everytime after that when the hero dies the demon king keeps them so they can't reunite with their lover in the afterlife. Female/male lead fight together to defeat him.

Kondo koso Shiawase ni Narimasu!

~4400 manga completed
~1700 ongoing...

Thank you so much!!!!