App de Deatta Yabai Yatsu

Kamiyama Kisa is a 27-year old OL with a secret. She's been with her boyfriend for six years and they were just about to consider marriage when she found out he'd cheated on her via a dating app. When she got on the app herself in retaliation, she matched up with an outrageous guy, and started a rather messy relationship!? (Source: Digital Margaret, translated)