I've read this yaoi manga years ago and I can't find it in my already or readi list unfortunately So it's about them falling in love during highschool (?) Then as years progressed on, they moved in together, and the top became more of a Yandere while the bottom became more submissige and likes it when the top gets obsessive over him. I remember the scene where he was invited out by his friends to meet up since it's been a while, despite the top telling him not to go anywhere (cuz he likes him at the house all day), he still went. So the top ended up going there too. After that when they went home, turns out the bottom has a plus in his hole the whole time keeping the top's cum there