Need help finding a yoai manga

There was a manga I read a while go that was yabdere boy x yandere boy. But they were childhood friends. The seme was less obvious about his yandere tendencies then the uke. One scene I remember was when they moved in together and the seme was excite because they had been together for 7 years and he now "owned all" of the uke. Something about all of the cells in the body being completely regenerated after 7 years.