After Divorcing Dazai, I Eloped with the Demon's Partner

Story blurb: My name is Ida Naoko. Three years ago, a kind Russian tipped me off that my ex-husband, Dazai Osamu, was juggling countless relationships. To clear the weeds from my own garden, I wasted no time in getting a divorce. But my ex-husband, as the leader of the Port Mafia, had too much power. Little and helpless, I had no choice but to leave my home with that equally meek Russian boss, flee to Siberia, and start a new life. Never in a million years did I expect that, when I set foot on this land again three years later, the dark-skinned older brother of my distant cousin's classmate would suddenly pop out of a cafe wearing a secret identity and tell me that the Russian man who planned to get engaged to me was conning me. I figured there must be some misunderstanding, so I planned to explain things to him. But just then, my ex-husband appeared before me with the first woman he had cheated on me with. Ex-husband: Dump that Russian and let's start over. Brother, you'd sound a bit more convincing if you weren't standing next to that young woman. So who gave you the nerve to say that to me with your new flame in tow? The pairing in this story is Fyodor. Theme: Let go of your obsession to find happiness.