Moshi Moshi Kame-san: Chinpira, JK no Papa ni Naru

Natsuha was raised in a single-parent household without a father since she was born. One day, her mother brings home her new husband. He looks like a yakuza who has just been released from prison...!? Meanwhile, Natsuha's boyfriend, who she just started dating, is preoccupied with their first time having sex...! Natsuha is confused by all the changes...!?

(Source: Shueisha, translated)