What kind of title is this?: Manga.
How many volumes are there?: 28 volumes are listed.
How many chapters are there?: 299 chapters are listed.
Where can I read it?: Reading links are listed for Kodansha USA, K MANGA. Check availability in your region.

Synopsis

About Domestic Girlfriend

High schooler Natsuo is hopelessly in love with his cheerful and popular teacher, Hina. However, one day at a mixer, he meets a moody girl by the name of Rui and ends up sleeping with her. Soon after, his father announces that he's getting remarried to a woman with two daughters of her own. And who shows up in tow, other than both Hina and Rui?! Natsuo's outrageous new life starts now! (Source: Kodansha USA) Note: Includes 23 extra chapters.

Drama Ecchi Romance Slice of Life