Age Gap

The leads stand a real distance apart in years, and the story treats the distance as terrain rather than scandal. The trope's honest subject is asymmetry: of experience, of settledness, of what each lead has already survived, and the appeal runs both directions, the younger drawn to someone finished being built, the elder to someone still deciding, and both to being chosen across the difference.

The desk grades on the levelness of the ground. Years often arrive carrying power, seniority, money, authority, and the craft standard is that any such gradient gets named and neutralised on the page, with the younger lead's agency doing visible work, because a romance that runs on the tilt rather than across it is a different book wearing this one's cover. The strongest versions let the gap raise real questions, timelines, families, what each wants the next decade to hold, and answer them as adults. The failure mode is the gap as flavouring, announced in the blurb, felt nowhere in the choices.