Relishatespickles

I can't remember much. All I remember that the mc was like a training priest, and he was really good at playing this one instrument during mass. He was told that he put to much emotion in it or something. Thanks

looking for a manhwa where the main character's job involves testing the fidelity of people's partners. She eventually meets a man at a bar, initially mistaking him for her target, and they start dating. There's also a subplot involving her boyfriend's friends, one of whom is an author, and another is cheating on his wife within their friend group.