I forgot the name

that one manga that the couple is a mentally impared guy and his caretaker i guess, anyways they live in a island (?) and they have a past together but the guy can't remember, i read it a long time ago and there was only 3-5 chapters translated at that time ://, I'm not finding it so probably i wasn't logged when reading it, anyways plz tell me u know what im talking about （￣へ￣）