Have you seen Two for the Road starring Audrey Hepburn and Albert Finney? It's one of my all time favorite movies. In it, you see the ups and downs of a relationship over the course of 12 years. Long term relationship stories are hard to find in romantic comedies. So many movies end with the boy and girl kissing and the audience is left to assume they live happily ever which we all know is not how it works in real life. With its non-linear plot and ability to include real aspects of a relationship, I guess you could call it a precursor to 500 Days of Summer.
Other random reasons this movie might interest you:
Someone at The Simpsons must love this movie too! A few years ago, the cartoon spoofed the movie.
Does Albert Finney look familiar? Try to imagine him a bit older, bald and singing with a red-headed orphan. That's right, he's Daddy Warbucks!
Also, a young William Daniels (Mr. Feeney from Boy Meets World!) costars as, well, a younger version of Mr. Feeney.