You know, I didn't even think of it like that (I must need my slash goggle re-tightened) but now you've said it, I can't help thinking how it reminds me of Holmes/Watson. Throughout the books/films/tv shows, Watson is constantly abandoning his wife to go gallivanting off with Holmes, most of the time not even waiting to tell her face to face, just leaving a quick note. (I imagine they go something like Off with Holmes. Don't wait up :p) And whilst the diner scene is like that in miniature form, I think it almost definitely used to happen when Peter & Janie were still together and almost certainly contributed to the break-up. Or so I like to think :)

Apologies for the minor Holmes ramble. Yes, I'm a bit of a Sherlock geek.