Transmigrated as the Foil? The Villainous Male Lead Insists on Spoiling Me

[1950s period setting + transmigrate into a book + devoted couple + ensemble cast of ordinary people + family life + no saintly heroine, no handouts] Song Manzhi transmigrated into a period novel she'd only read the beginning of. What she didn't know was that she'd become the foil. Other foils get trampled into the dirt and made into stepping stones for the heroine. But someone had secretly rewritten the script for this foil: She doesn't have an overpowered golden finger, and she doesn't make a name for herself by taking down awful relatives. She simply puts the knowledge she gained in her previous life to use, and makes a wonderful life for herself in the 1950s…