RE:MARINA

Rinnosuke's useless and vagrant father is now dead. Now, at the age of 16, he is completely alone and will have to quit school to survive. On the night his father dies, a naked woman with large breasts falls from the sky and lands on top of him. She introduces herself as Sakamoto Marina, the future wife of the future Rinnosuke. She states that she used a time machine to come back to the past, and start a new life with the younger Rinnosuke. Rinnosuke's new life with his future(?) wife begins. — Description from AniList community (anilist.co).