Read this one a couple of years ago, I don't think it was ever finished. It was about a relationship between a guy and girl, and whenever they would get too close the girl would just disappear into thin air. After a while the girl would reincarnate into a different form and approach the guy again. Same deal, whenever they would get to know each other and become close she would disappear again along with all memory (except the mc's) of her being erased, and the cycle begins anew.

Is this it?
[url]https://www.mangaupdates.com/series.html?id=94733[/url]

🙂

You did it! I am incredibly grateful