A Scorned Wife's Revenge: A Worthless Groom

Asuka had always dreamed of a romantic proposal, but when the time came, all she got from her live-in boyfriend of seven years, Yuta, was a casual "How about we get married?" over dinner at their local bar. He didn't even put down his phone or look her in the eyes! She goes off on him (in her mind) but then reminds herself to be realistic and accepts his proposal. As the wedding approaches, she finds an open box of condoms while cleaning one day... and notices that only one is left, even though she can't remember using any of them with Yuta. That's all the proof she needs: the bastard is cheating on her!!

(Source: MangaPlaza)