To be exact, the male lead is the son of a serial killer and is traumatized from his father's antics. Can't remember if he became a serial killer too, killed some people, or not. But I remember him imprisoning someone with possible torture because to be fair, that guy's the other villain in the story and tried harming his family. As for his other occupation, he owns a shop where he creates stuff, either iron works or wood.
And the female lead is in the justice department, I'm just not sure if her position was as a detective or a police officer. They met during their college days, got married, and now, have a daughter together around kindergarten or grade 1 age. But despite being married for a while, they're still at the honeymoon phase.
And then comes the murder part. I watched this show with someone mid-way the series, so I don't remember the details but he's suspected of being a serial killer by the FL's co-worker since all evidence is leading to him.
I remember the climax: they were at a cliff side with all the other officers. ML was hallucinating his father was there and was crying for her to get away from both his "father" and himself. The FL was trying to comfort him from a distance that everything was okay, and to get him away from the cliff side. And I think something happened that made one of the officers shoot him.
At the ending, he lost his memories up until college before meeting her. He planned to separate ways with the FL but after seeing and listening about what they were to each other, the shop he dreamed of and had built with his family, and holding their daughter in his arms, he decides to stay with them and try to became that loving father and husband again.
I'm sorry for the crappy description but I hope it triggers a memory at least. I really want to properly watch the series this time. The couple were sweet together, there were wholesome family moments, it had good mystery aspects that kept me on edge, and had that sad revelation which I dig. I'd greatly appreciate your help in identifying this! ??