It's a chinese WN I forgot the title. MC is female, transmigrated into a novel book but only realized it's a book years after marriage with ML (Iirc). She is a very calm and serene person. They married bcos ML was heartbroken by his white moonlight (not novel's protag), and paired with MC so to forget those memories. MC character setting in novel was that she's in love with ML's white moonlight's husband, but after the transmigration, ofc, she doesn't. MC doesn't really bother with OGplot , either. She thinks of it time to time and wondered if it'll came true, but didn't fuss on it. If it happens she thought she'll just divorce and left calmly. OGplot FL is a simple waitress that had a luck encounter with ML. In the OGplot, ML and wife has a very bad relationship bcos of their unforgotten past love, but after MC came along they had a nice marriage life and ML transform into wife-slave. There's a scene in early chapters where ML's friends visited, saw their house's balcony filled with potted plants, and thought to himself, "i see why he's settled down now, that woman makes this place a true home" (Or something like that). Also there's a scene where friends are shocked to see ML obediently following his wife's instruction to do chores. At one point further (I read through MTL), MC randomly think of the plot and mistakenly said to ML, "hmm im thinking of divorce", made ML furious, and they talked it out. After that point, MC became pregnant, and soon she forgot all about the novel, even forgotting there's a protagonist in her world. The two had a baby and happy life after.
Glad to help! Since I haven't read past the third chapter in order to stockpile the translated ones, I'm not too sure either
It's okay since I tend to find spoilers that are available before reading any books it's rare for me to not searching for them