Futago, Futagokoro.

Futago, Futagokoro. manga summary: It's the ultimate romantic comedy of a non-riajuu boy and two polar opposite sisters! Haruta is going out with a shy beauty, Mafuyu. While he's distressed over being unable to even hold hands, he was able to enjoy youth with his girlfriend for the first time in his life. However, having encountered Mafuyu's devilish twin sister who's the extreme opposite of her, his happy days are coming to an end!?