Looking for books about lovers reuniting after years, with past/present flashbacks

I’m looking for well-written M/F books where two lovers reunite after many years apart, and the story uses past/present flashbacks to show how their relationship began, what went wrong, and why the connection still lingers.

I’d especially love stories that are sweet, emotional, and full of yearning, where you can really feel how much the characters still care about and remember each other…