Flirting with a Pure-Hearted Straight Guy Backfires, and the Top Player Panics

Two male leads, 1v1, younger puppy-type top, husband-pursuit, lighthearted, happy ending, urban. Innocent straight top VS gorgeous playboy bottom. (A melodramatic story about the rich, handsome eldest young master of the Lan family, who shuts his heart away and lives it up among lovers, only to fall for a college student who has just turned twenty.) Content warning: The bottom is a playboy at first and has prior sexual experience. The top is completely inexperienced in both body and heart.