Instead of high school rivals, make them professional competitors or neighbors who have disagreed for a decade.
Mature characters generally have a lower tolerance for "misunderstanding" tropes. sexy sex mature women
Conflict often involves caring for aging parents while managing relationships with adult children. A romantic storyline can be heightened by the lack of "alone time." Instead of high school rivals, make them professional
Use dialogue that is clear. Mature lovers are more likely to say, "I don't have time for games," than to spend three chapters wondering why a text wasn't returned. Instead of high school rivals